Sunday

February 14, 2016
Total # Posts: 1,926

**chemistry**

Fe2O3(s)+3CO(g)--->2Fe(s)+3CO2(g) we see that this chemical equation is already balanced. to get the number of moles of CO, we multiply the given moles of Fe2O3 by the stoichiometric ration from the balanced equation,, thu 1.75 mol Fe2O3 * ( 3 mol CO / 1 mol Fe2O3 ) = 5.25 ...
*April 11, 2011*

**math**

1/4 of 48 means you multiply 1/4 by 48. 1/4 * 48 note that we can rewrite 48 as 48/1 since any number divided by 1 is equal to itself. thus rewriting, 1/4 * 48/1 to multiply fractions, we multiply numerator by numerator and denominator by denominator. (note: numerator-the ...
*April 11, 2011*

**maths**

h t t p : / / w w w . w o l f r a m a l p h a . c o m / i n p u t / ? i = y % 3 D x + a n d + y % 3 D x ^ 2 - 6 x - 1 0 ..without the spaces~ :)
*April 11, 2011*

**algebra 1**

you forgot to multiply 20 by 8: n+8(n+20)=110 must be n+8n+160=110 but you're on the right track~ :)
*April 11, 2011*

**math**

first we represent unknowns using variables,, let x = first number let x+2 = second number note that since they are consecutive but both even numbers, the difference between them is 2, that's why the second number is x+2 now we set-up the equation,, since the sum of the ...
*April 10, 2011*

**math**

first represent unknowns using variables,, let x = first number let x+1 = second number note that the second number is x+1 because they are consecutive numbers. now we set up the equation,, according to problem, their product is 240, thus: x(x+1) = 240 x^2 + x = 240 x^2 + x - ...
*April 10, 2011*

**math**

first we represent the unknowns using variables,, let x = width let 3x-3 = length (according to the first statement) now we set up the equation,, since we are given the area, recall that the area of a rectangle is A = L*W where L=length and W=width. substituting, 90 = (3x - 3...
*April 10, 2011*

**elementry algebra**

since this equation is already in the slope-intercept form, we can readily determine the slope and y-intercept. note that in slope-intercept form , y = mx + b, m is the slope ; and b = y-intercept thus in the given equation, y = 2x + 2 m = 2 ; and b = 2 since y-intercept is a ...
*April 10, 2011*

**math**

for (1), a^2 * b^(-3) note that when a term is raised to a negative exponent, we get its reciprocal and raise it by the positive exponent,, for example, 2^(-4) = 1/(2^4) ; thus we can rewrite b^(-3) = 1/(b^3) therefore, a^2 * (1/(b^3)) a^2 / b^3 for (2), (5/3)^-3 we do the ...
*April 10, 2011*

**chemistry**

assuming the gas is ideal, we can use the formula, P1*V1/T1 = P2*V2/T2 where P1 = initial pressure V1 = initial volume T1 = initial temperature (in K) P2 = final pressure V2 = final volume T2 = final temperature (in K) we first convert the given temp to Kelvin units: T2 = 12...
*April 10, 2011*

**Calculus**

ahh i think i know why y = (a+b)/2 is wrong,, it's actually the MINIMUM, not the maximum~ ^^; i tried assigning some values to the variables,, and from the graph, rate -> infinity at y -> inifinity , or at a finite value of a and b, when the reaction is at completion...
*April 10, 2011*

**Calculus**

for (a) since a < b , for a certain value of y , the value of (a - y) will become negative first, and thus the Rate becomes negative,, then after some time (b - y) will become negative too, and the Rate becomes positive. let's look at some points: at 0 <= y < a , ...
*April 10, 2011*

**jordan high**

umm i think in the problem, you mean "the volume DECREASES",, assuming the gas ideal, we can use the formula P1*V1 = P2*V2 where P1 = initial pressure V1 = initial volume P2 = final pressure V2 = final volume *this equation is Boyle's Law substituting, 0.63 * 324...
*April 10, 2011*

**calculus**

antiderivative = integral to get the integral of this, note that we can rewrite (cos x)^3 as (cos x)(cos x)^2 . then recall that (cos x)^2 = 1 - (sin x)^2 ,, rewriting: integral of [ (cos x)(1 - (sin x)^2) ] dx then we let u = sin x ; and thus du = cos x dx substituting these...
*April 9, 2011*

**Algebra**

x + (1/6)y = 1/2 to transform this into y = mx + b, first we isolate the y term into the left side of equation,, thus the x on the left side must be transposed to the right side. to do this we change the sign of x to its opposite (positive becomes negative): x + (1/6)y = 1/2 (...
*April 9, 2011*

**maths(urgent....please...)**

hello arun~! i think i also answered this yesterday,, i'll just re-post my solution here. if there's something you didn't understand, feel free to ask. :) first we observe that the motion of the ball is projectile and its trajectory (path followed by the ball) is ...
*April 9, 2011*

**Math**

you mean (7x^2-18x-7)/[(x-4)(2x^2-6x+3)] ? if so, it cannot be further simplified.
*April 9, 2011*

**algebra**

note that you cannot combine radical terms if their radicands (the terms inside the radical sign) are not equal. for example, sqrt(8) + sqrt(18) you cannot add them right away since 8 is not equal to 18,, thus we first simplify each term. for sqrt(8), note that we can rewrite ...
*April 9, 2011*

**Physics**

note that voltage is constant across each resistor. also in parallel circuit, the sum of the currents across each resistor is equal to the total current,, since there are only two resistors in the circuit in the problem, I1 + I2 = I,total substituting, 1 + I2 = 3 I2 = 3-1 = 2 ...
*April 9, 2011*

**math**

recall that speed is distance travelled per unit time, or v = d/t since the given speed is in miles per hour, we first convert the given time (the 12 minutes) to hours: 60 minutes = 1 hour ; thus 12 minutes = 0.2 hour substituting, v = d/t 35 = d/0.2 d = 7 miles hope this ...
*April 8, 2011*

**physics**

recall that I = V/R where I = current (in Amperes) V = voltage (in Volts) R = resistance (in Ohms) substituting, I = 6.7/70 I = 0.0957 A hope this helps~ :)
*April 8, 2011*

**algebra**

let's put parenthesis so that it's not so confusing: (x-1)/(x-9) - (x+1)/(x+9) + (x-153)/(x^2-81) first we get the least common denominator (LCD) of these,, observe that (x-9)*(x+9) = x^2 - 81 . thus the LCD is equal to x^2 - 81 . multiplying all terms by (x^2-81)/(x^2...
*April 8, 2011*

**Physics**

recall that speed is distance traveled per unit time, or v = d/t also recall that work is force exerted times distance, or W = Fd since in the problem we are only given the force, we calculate for the distance first. substituting the given speed and time to formula for speed: ...
*April 8, 2011*

**Chemistry 1001**

note that gases are more soluble in higher pressures, thus CO2 gas will be most soluble in 900 torr. i think the most common example (observation) for this is when you open a carbonated drink,, before it is opened, CO2 gas is dissolved in the liquid. when you open the bottle, ...
*April 8, 2011*

**Maths**

first we represent unknowns using variables,, let x = number of boys let y = number of girls according to first statement, ratio of boys to girls is 3:2 or 3/2 . thus we can write, x/y = 3/2 or x = (3/2)*y according to second statement, there are 11 more boys than girls, thus...
*April 8, 2011*

**math**

first we represent the unknowns using variables: let x = length according to first statement, the width is 1 more than half the length,, thus let (1/2)x + 1 = width now we set up the equation,, since we are only given the area, we can use this to solve for length and width. ...
*April 8, 2011*

**algebra2**

y = 8*(3^x) recall that domain is the set of all possible values of x,, here there is no restriction for x thus the domain is all real numbers. recall that range is the set of all possible values of y,, here note that y cannot be negative since the term 3^x is always positive ...
*April 8, 2011*

**math**

y = x^2 + 2x - 15 y = (x - 3)(x + 5)
*April 8, 2011*

**chemistry**

assuming the gas is ideal, we can use the formula, V1/T1 = V2/T2 where V1 = initial volume T1 = initial temperature (in K) V2 = final volume T2 = final temperature (in K) we first convert the given temp to Kelvin units: T1 = 7 + 273.15 = 280.15 K T2 = 15 + 273.15 = 288.15 K ...
*April 8, 2011*

**Math!!!!!!HELP!!! :(**

kilogram is a unit of mass while gallon is a unit of volume. you can relate them by using density of a particular substance (density is mass per unit volume or d = m/V) for example, if we consider water, which has a density of 1 g/mL or 1 kg/L, and recalling that 1 gallon is 3...
*April 8, 2011*

**math**

do you mean how many hours will it take for the feeder to give all of the food he/she is holding? if so, then we first convert 3 kg to grams: 1 kg = 1000 g ; thus 3 kg = 3000 g now we divide 3000 by 150 to get the time needed: 3000 / 150 = 20 hours hope this helps~ :)
*April 8, 2011*

**math**

recall that speed is distance travelled per unit time, or v = d/t since they are travelling towards each other, we add their speeds (since travelling towards each other consumes less time for them to meet than travelling in the same direction) substituting, v = d/t 610 + 618...
*April 8, 2011*

**MATH VERY URGENT!!!!!!**

first we observe that the motion of the ball is projectile and its trajectory (path followed by the ball) is shaped like a parabola. the horizontal distance travelled by the ball is thus given by: R = (vo)^2 * sin (2*theta) / g where R = range or the horizontal distance vo = ...
*April 8, 2011*

**science**

to get the heat released or absorbed, Q = mc(T2-T1) where m = mass of substance c = specific heat capacity T2 = final temperature T1 = initial temperature **note: if Q is (-), heat is released and if (+), heat is absorbed now we can only apply this to substances that did not ...
*April 8, 2011*

**MATH URGENT!!!!**

for (a), we substitute 17 to d in the equation for the height,h: h = -0.045d^2 + 2d h = -0.045*(17^2) + 2(17) h = 20.995 yards for (b), we are given the height and we need to find the horizontal distance. substituting, h = -0.045d^2 + 2d 8 = -0.045d^2 + 2d 0 = -0.045d^2 + 2d...
*April 8, 2011*

**calculus**

observe that we can further simplify (|x+h|-|x|)/h to (x + h - x)/h (h)/h 1 rewriting, lim 1 as h->0 at x = 4 is equal to 1, since the limit of a constant is also equal to that constant. hope this helps~ :)
*April 8, 2011*

**Physical Science**

to get the heat released or absorbed, Q = mc(T2-T1) where m = mass of substance c = specific heat capacity T2 = final temperature T1 = initial temperature **note: if Q is (-), heat is released and if (+), heat is absorbed now we can only apply this to substances that did not ...
*April 8, 2011*

**chemistry **

assuming that the gas is ideal, we use the formula for ideal gases: PV = nRT where P = pressure (in atm) V = volume (in L) n = number of moles R = gas constant (0.0821 L*atm/mol-K) T = temperature (in Kelvin) we first convert the 26 degrees Celsius to Kelvin: 26 + 273.15 = 299...
*April 8, 2011*

**geometry**

since the lengths of sides of the flag are equal, the shape of the flag is a square. recall that the area of square is A = s*s where s = length of a side of square. substituting, A = 60*60 A = 3600 square cm hope this helps~ :)
*April 8, 2011*

**chemistry **

assuming that the gas is ideal, we use the formula for ideal gases: PV = nRT where P = pressure (in atm) V = volume (in L) n = number of moles R = gas constant (0.0821 L*atm/mol-K) T = temperature (in Kelvin) we first convert the 26 degrees Celsius to Kelvin: 26 + 273.15 = 299...
*April 8, 2011*

**MATH URGENT!**

first we observe that the motion of the ball is uniformly accelerated motion (because of acceleration due to gravity while it's in the air), thus we use this formula to find time: h = ho + vo*t - (1/2)*g*t^2 where ho = initial height vo = initial velocity t = time g = ...
*April 7, 2011*

**geometry**

recall that area of trapezoid is A = (b1 + b2)*(h/2) where b1 and b2 are the bases of trapezoid h is the height substituting, 4 = (b1 + b2) * (1/2) 8 = b1 + b2 now we list two number whose sum is 8: 1 and 7 2 and 6 3 and 5 4 and 4 these are the possible lengths of bases. hope ...
*April 7, 2011*

**Math**

hmm,, recall that when we consider a parallelogram, we also consider square, rhombus, and rectangle (they are all parallelogram) now, let's analyze each choices: for (a), it's only true for a square. for (b), it's true for square and rectangle. for (c), it's ...
*April 7, 2011*

**algebra**

do you mean, 13/18 divided by 20/27 ? if so, then we first get the reciprocal of the divisor (the second term; that is, 20/27) ,, thus its reciprocal is 27/20 (note that reciprocal is just interchanging the numerator and denominator) now the process becomes multiplication. to ...
*April 7, 2011*

**geometry**

first represent unknowns using variables: let x = length of rectangle let x-6 = width of rectangle (according to first statement of problem) now we set up equation,, since in the problem we are given the perimeter, we can use this to set up the equation,, recall that perimeter...
*April 7, 2011*

**math**

triple 4 means 3 times 4: 3 x 4 = 12 since we subtract 2 from 12 each day , we need to divide 12 by 2 to get the number of days needed to reach zero: 12 / 2 = 6 days hope this helps~ :)
*April 6, 2011*

**Math 8th Grade**

there are many possible answers here. one answer could be the length of longer = 14 m and shorter = 9 m it can also be longer = 18 m and shorter = 7 m .. i think you forgot an information in the problem,..
*April 6, 2011*

**Algebra **

yes
*April 5, 2011*

**Pre Algebra**

x: 0 1 2 3 y: 5 4 3 2 to get the function, we choose two points. let's just choose the first two points,, that is, point1 (0,5) and point2 (1,4) now, we get first the slope. the slope is given by the equation, slope = m = (y2 - y1)/(x2 - x1) where y1 = y-coordinate of ...
*April 5, 2011*

**Geometry**

first, we represent the unknowns using variables: let x = number of 5-dollar bill since according to first statement, he has a total of 124 bills in 5 and 10, let 124 - x = number of 10-dollar bill now we set up the equation,, according to the second statement, the total value...
*April 5, 2011*

**chem**

first write the chemical equation: HCl + NaHCO3 -> NaCl + H2O + CO2 observe that it's already balanced. :) now we get the molar mass of NaHCO3 (sodium bicarbonate) and HCl (hydrochloric acid),, i expect you already know how to find molar masses. NaHCO3 : 23 + 1 + 12 + 3...
*April 5, 2011*

**chemistry**

recall that density is mass per unit volume, or d = m/V substituting, d = 100/200 d = 0.5 g/mL hope this helps~ :)
*April 5, 2011*

**chemistry**

recall that 1 mole = 6.022 x 10^23 atoms thus, 0.32 * (6.022 x 10^22) = 1.927 x 10^23 atoms hope this helps~ :)
*April 5, 2011*

**math**

always remember E.M.D.A.S. = Exponents, Multiplication, Division, Addition, Subtraction. this the order of which operation must be done first. here, of course we start with the operation inside the parenthesis: 5+(3x3-3)/2 5 + (9-3)/2 5 + 6/2 5 + 3 8 hope this helps~ :)
*April 5, 2011*

**math**

it means you will multiply 4/5 by 25,, thus 4/5 * 25 note that we can rewrite 25 as 25/1 (since any number divided by 1 is equal to itself),, rewriting, 4/5 * 25/1 to multiply fractions, we multiply numerator by numerator and denominator by denominator. note: numerator is the ...
*April 5, 2011*

**Chemistry**

Single Replacement Reaction~
*April 4, 2011*

**math**

note that a reflex angle is an angle greater than 180 degrees bu less than 360 degrees,, first, since the digits are factors of 8, we list all factors of 8: 1, 2, 4, 8 since the digits are even and are different, the digits of the reflex angle we're looking for are 2, 4 ...
*April 4, 2011*

**Math**

to do this, first we know that there are 18 ways for the first place (since there are 18 dogs), then 17 ways for the second place (18-1=17 since no dog can win two places), and 16 ways for the third. thus, we multiply these to get the number of ways: 18*17*16 = 4896 ways hope ...
*April 4, 2011*

**Math**

to do this, first we multiply the 1st terms or the number with no exponent (not the terms with 10 raised to an exponent). thus: 4.3*2 = 8.6 now we multiply the 2nd terms,, recall that if they have the same base (here, the base is 10) we can simply add the exponents: 10^3 * 10...
*April 4, 2011*

**Math**

to get the total weight, we multiply them: 2x10^(-5) * 1x10^15 to do this, first we multiply the first terms or the terms with no raised exponent,, thus that would be the 2 and 1: 2 * 1 = 2 next we multiply the second terms or the 10 raised to exponent,, to do this, recall ...
*April 4, 2011*

**Geometry**

to do this, we calculate both of the circles' circumference. the bigger circle has diameter of 26 in, while the smaller has diameter of 18 in. now recall that the circumference of a circle is given by C = 2*π*r or given the diameter, C = π*d where π = ...
*April 4, 2011*

**math**

when an object is dropped from a certain height, it is a freefall. when in freefall, the only external force acting on the body is gravitational force (neglecting air resistance). the motion of the object is unformly accelerated motion: (v2)^2 - (v1)^2 = 2*g*h where v2 = final...
*April 4, 2011*

**math2**

first, we list the factors of each number,, 15: 1, 3, 5, 15 34: 1, 2, 17, 34 55: 1, 5, 11, 55 since the only common factor among them is 1, the greatest common factor (GCF) of the numbers is 1. hope this helps~ :)
*April 3, 2011*

**math**

first, we convert 9 Liters to milliliter,, recall that 1 L = 1000 mL, thus 9 L = 9000 mL now we divide 9000 by 90 to determine how many 90 mL-bottle she needs: 9000 / 90 = 100 bottles hope this helps~ :)
*April 3, 2011*

**chemistry**

you need a periodic table of elements. in the periodic table, you can find certain properties of elements and and also atomic number and atomic mass. since in the problem, we are required to calculate for molar mass of H2O, you look for H and O in the periodic table and get ...
*April 1, 2011*

**Chemistry**

first write the balanced chemical equation: C3H8 + 5O2 -> 3CO2 + 4H2O **note: in combustion reaction of organic compounds, the usual products are carbon dioxide and water. then calculate for molecular weight of propane (the C3H8),, Carbon is 12 while H is 1: 3*12 + 8*1 = 44...
*April 1, 2011*

**physics urgent please **

an example of projectile motion would be the motion of the baseball when it is hit by the bat,, it the trajectory (the path followed by the object) has the shape like a parabola. projectile motion is possible because of gravity. about the velocity, since it followed a path ...
*March 31, 2011*

**algebra **

domain is the set of all possible values of x, while range is the set of all possible values of y. for example, y = x^2 since any values of x can be substituted here, we say that the domain is all real numbers (zero, positive and negative numbers -- any number actually ) while...
*March 31, 2011*

**math**

x squared is usually typed like this: x^2 (means x raised to two) :) anyways, the given in y = x^2 - 6x - 8 and we need to find x when y = 1. thus we substitute y into the equation: y = x^2 - 6x - 8 1 = x^2 - 6x - 8 now to solve for x,, first we make one side of the equation ...
*March 31, 2011*

**Math**

we can also rewrite this (a+b)squared=64 as (a+b)^2 = 64 first we expand (a+b)^2 (a+b)^2 = 64 (a+b)(a+b) = 64 a^2 + 2ab + b^2 = 64 since we are given the value of ab, which is ab = 3, we can substitute it here: a^2 + 2(3) + b^2 = 64 a^2 + 6 + b^2 = 64 a^2 + b^2 = 64 - 6 a^2 + ...
*March 31, 2011*

**math**

that 'n' is actually the Greek letter π which is equal to 3.1416... but since in the problem π = 22/7 , we use this value. recall that the area of a circle is given by A = π*r^2 where r = radius substituting, A = π*(7^2) A = (22/7)(49) A = 22*7 A = ...
*March 31, 2011*

**Algebra**

since it's 30 by 30, the shape is a square. recall that the diagonal of a square is given by: diagonal = sqrt(s) where s = length of a side thus, the diagonal is sqrt(30) hope this helps~ :)
*March 31, 2011*

**math **

if the given sequence is a geometric sequence, then it follows the formula A,n+1 = r*(A,n) where r = ratio between two consecutive terms A,n = the nth term A,n+1 = the term after A,n substituting the first and second term, 40 = r*16 r = 40/16 r = 2.5 to check, let's see if...
*March 31, 2011*

**physics**

recall that pressure is force per unit area or P = F/A first of all, we convert 10 cm^2 to m^2 for consistency of units (since the unit Newton is actually kg*m/s^2),, therefore 10 cm^2 (1 m / 100 cm)^2 = 0.001 m^2 substituting, P = 180/0.001 P = 180000 kg/(m*s^2) = 180000 Pa (...
*March 31, 2011*

**math**

(fog)(x) = f(g(x)) = [g(x)]^2 (fog)(x) = [sqrt(x-3)]^2 note that the sqrt and ^2 will just cancel each other out: (fog)(x) = x - 3 to find its domain,, recall that domain is the set of all possible values of x,, since we both considered f(x) and g(x) here, we find the ...
*March 31, 2011*

**math**

(gof)(x) means you substitute the whole expression of f(x) to g(x): (gof)(x) = g(f(x)) = f(x) + 1 (gof)(x) = x + 1 for #2, we do the same,, we substitute f(x) to f(x): (fof)(x) = f(x) (fof)(x) = x hope this helps~ :)
*March 31, 2011*

**math**

first we can actually substitute f(x) by y, thus f(x) = 3 - 5x y = 3 - 5x to get the inverse, interchange the x and y variables,, thus x = 3 - 5y now, we solve for y: x = 3 - 5y x - 3 = -5y y = -(x-3)/5 then we substitute back f(x) to y, but this time since we get its inverse...
*March 31, 2011*

**math**

(fog)(x) means you substitute the whole function of g(x) into the f(x),, we can actually rewrite this (fog)(x) as f(g(x)) --- i think this one is clearer. now let's substitute g(x) to f(x): (fog)(x) = f(g(x)) = 3x-5 = 3[g(x)] - 5 (fog)(x) = 3(2 - x^2) - 5 (fog)(x) = 6 - 3x...
*March 31, 2011*

**Chemistry**

to get the heat released or absorbed, Q = mc(T2-T1) where m = mass of substance (units in g) c = specific heat capacity (units in J/g-K) T2 = final temperature T1 = initial temperature **note: if Q is (-), heat is released and if (+), heat is absorbed now we can only apply ...
*March 31, 2011*

**math**

recall that the area of a triabgle is given by A = (1/2)*bh where b = base h = height substituting, A = (1/2)(b)(12) A = 6b hope this helps~ :)
*March 31, 2011*

**Matt 116 Algebra**

what about y = 45x + 12 ? do you need to graph it ? or solve for x in terms of y ?
*March 31, 2011*

**math**

to solve this you divide 4.7 by 1, then multiply by 100: 4.7/1 * 100 4.7 * 100 = 470% hope this helps~ :)
*March 31, 2011*

**math**

4*3*2 = 24
*March 31, 2011*

**Algebra 1A**

i suppose this means that (17,8) is a point on the graph or a solution to the equation,, if so, it means we need to find for the slope, m. substituting the x- and y-coordinate to the equation: y = mx - 16 8 = m(16) - 16 8 + 16 = 16m 24 = 16m 24/16 = (16/16)m 3/2 = m rewriting ...
*March 31, 2011*

**math**

recall that the volume of a cylinder is given by V = pi*r^2*h where r = radius h = height substituting, V = pi*(8^2)*(7) V = 3.14*64*7 V = 1407.43 cubic km hope this helps~ :)
*March 30, 2011*

**math**

your answer is correct. :)
*March 30, 2011*

**english**

the verb is: resumed
*March 30, 2011*

**Algebra**

2a - b = ac + 3b to get a, first we need to transpose all terms containing a to one side of equation, and all other terms to the other side,, in this case the terms containing a are 2a and ac. let's just transpose them to the left side of equation,, since ac is on the ...
*March 30, 2011*

**math algebra**

do you mean something like this: [2(a^10)(b^2)][3(a^2)(b^2)] if so, then for constants, we just multiply them normally,, for the variables, recall some laws of exponent,, multiplying terms of same base is also equal to base raised to sum of its exponents,, for example 5^2 * 5^...
*March 30, 2011*

**math**

recall that area of square is A = s*s where s = length of a side of square therefore, substituting the given area: 36 = s*s 36 = s^2 get the squareroot 6 = s thus the length of side of square is 6 units. hope this helps~ :)
*March 30, 2011*

**algebra**

4xx - 36 can also be written as 4x^2 - 36 to factor this, notice that 4x^2 and 36 are both perfect squares (meaning they have an exact squareroot),, and 4x^2 - 36 is a difference of two squares. recall that if an expression is in the form (a^2 - b^2) it can also be written as...
*March 30, 2011*

**Math**

first recall that perimeter of a rectangle is P = 2(L+W) where L = length W = width substituting, 12 = 2(L+W) 6 = L+W now we need to find for positive, nonzero integers whose sum is 6,, the possible values are: L=5 and W=1 L=4 and W=2 L=3 and W=3 (this is a square but note ...
*March 29, 2011*

**math**

recall that the equation of a circle is given by (x-h)^2 + (y-k)^2 = r^2 where h = x-coordinate of the center k = y-coordinate of the center r = radius since in the problem, the center lies at (-8, -4) we have h = -8 k = -4 also, we need to solve for the radius from the ...
*March 29, 2011*

**geometry**

recall that the area of rhombus is just A = b*h where b = base and h = height we already have the base, which is 5 cm. we need to find for the height,, to get this, observe that if we draw the rhombus and draw a broken line representing the height, we see that a right triangle...
*March 29, 2011*

**Pre calc**

first we can transpose the - lnx to the right side of equation, 0.5 ln (x+3) = ln x recalling some laws of exponents, we can rewrite 0.5 ln (x+3) as ln (x+3)^0.5 therefore ln (x+3)^0.5 = ln x now we can equate the terms inside the ln: (x+3)^(1/2) = x square both sides: x+3 = x...
*March 29, 2011*

**Algebra**

note that we can rewrite the squareroot of a number by raising this number by 1/2 example, sqrt(5) = 5^(1/2) therefore in the problem we have sqrt(14abc) = (14abc)^(1/2) = [14^(1/2)][a^(1/2)][b^(1/2)][c^(1/2)] sqrt(2ab) = (2ab)^(1/2) = [2^(1/2)][a^1/2][b^1/2] now for the ...
*March 29, 2011*

**science**

recall that density is mass per unit volume, or d = m/V thus you need mass of the wooden block, and its volume,, to get mass you can use appropriate weighing scale and for the volume, you can measure its length, width and height since the volume of a rectangular solid (this is...
*March 29, 2011*

**math**

to find the slope of the line, we transform this given equation in the form, y = mx + b where m = slope and b = y-intercept thus for (1) 7x + 13y = 91, we first divide all term by numerical coefficient of y (which is 13) to get y alone: (7/13)x + (13/13)y = 91/13 (7/13)x + y...
*March 29, 2011*

**trig**

recall that cos x = sin (90-x) 90-x = 90-54 = 36 thus cos 54 = sin 36 hope this helps~ :)
*March 29, 2011*

**math**

to round a number to the nearest thousands: first find the digit in the thousands place, then look at the number to the right of the thousands place,, if this number is greater than or equal to 5, add 1 to thousands place; less than 5, thousands digit remains the same in the ...
*March 29, 2011*