Saturday

July 26, 2014

July 26, 2014

Total # Posts: 1,493

**math**

all numbers are correct. :) the last one, 2 3/16, i think it's fine in mixed number form.

**substitution method**

(1)3x + 8y = 33 (2) x = 31 - 6y when using substitution method, first you choose an equation (either of the two given) and express one of the variables in term of the other,, in this case we choose the equation (2) since x is already expressed in terms of y: x = 31 - 6y then s...

**algebra**

A = 1/2 * bh plug in the values: A = 1/2 * (28)(38) A = 532 m^2 so there,, :)

**algebra**

volume of solid = Area of the base * height therefore: 120 = 30 * h h = 4 m so there,, :)

**Algebra PLEASE HELP**

oh, alright mr. Damon. :)

**Algebra PLEASE HELP**

argh. alrighty~ :) (1) 2r - 5s = -12 (2) 5r + 2s = 57 to solve using elimination, you have to multiply a factor into the equation so that when you add/combine them, one of the variables gets eliminated or canceled out,, here, to deal with whole numbers, we multiply equation (1...

**Algebra PLEASE HELP**

(1) 2r - 5s = -12 (2) 5r + 2s = 57 when using substitution method, first you choose an equation (either of the two given) and express one of the variables in term of the other,, in this case we choose the equation (1) and express variable 'r' in terms of 's': 2...

**math**

for the first one, convert the mixed number into improper fraction: 10 4/5 = 54/5 *how to do it: multiply the denominator (which is 5) by the whole number (which is 10) then add the numerator (which is 4), thus 5*10 + 4 = 54,, while the denominator is still 5, thus it's 54...

**physics**

i think you mean it's weight (units in N), because mass is constant. anyway, since the weight increased, the elevator accelerates and moves up. :)

**math!!!!!!! help**

the answer was around five because if you look at (15 1/3) * (1/3) we can estimate 15 1/3 to 15 and 15 * 1/3 is 5,, when you look at the answer, 46/9, when converted to mixed number, it's 5 1/9 which is close to 5. so there,, :)

**math!!!!!!! help**

to multiply this, convert first the mixed number into improper fraction, 15 1/3 = 46/3 *how to do it: multiply the denominator (which is 3) by the whole number (which is 15) then add the numerator (which is 1), thus 3*15 + 1 = 46,, while the denominator is still 3, thus it'...

**math**

yes, that's right. :) then (42-45)/15 = -3/15 = -1/5

**MATH-STUCK**

i'm not sure if i get the picture but do you mean, 1/[9^(5/3)] if it is, let's focus on the 9^(5/3). let's make 5/3 into 5* 1/3,, the 5 here means you raise 9 into power of 5, or 9^5,, the 1/3 means "cuberoot" of 9 (thus if it's 1/2, it's "sq...

**math**

1 dm = 10 cm ,therefore, 80 dm = 800 cm *just multiply by 10 so there,, :)

**Math 111**

remember the form, y = a(x-h)^2 + k where (h,k) is the vertex, and x and y are points on the graph,, therefore, solving for a, 170 = a*(8-(-1))^2 + 8 170 = a*81 + 8 81a = 162 a = 2 therefore, y = 2(x+1)^2 + 8 expanding this, y = 2x^2 + 4x + 10 so there,, :)

**algebra**

-15*e^6*d^4

**Math**

what do you mean by the mean is 11 and the mean is 10?

**algebra**

1/2+7x/10=13/20 *multiply all terms by 20 to get whole number values: 10 + 14x = 13 14x = 3 x = 3/14 so there,, :)

**math**

i interpreted this into two ways. first, x+4(y+8x) distribute 4 to each term inside the parenthesis (you multiply 4 to each): x + 4y + 32x then add similar terms (terms containing same variable): 33x + 4y second interpretation, (x+4)(y+8x) use FOIL method: F-first terms in bot...

**Math - derivative of f(x) (check)**

yes, your answer is correct. :) i think that simplification means to factor 6x(x^2-1)^2 into 6x[(x-1)^2][(x+1)^2]

**Math - derivative of f(x) (check)**

yes, that's the derivative. did you expand your answer? or how did you do it?

**math**

first, notice that you can group the first two terms, and the last two terms, (2x^3-7x^2)+(4x-14), and factor: (x^2)(2x-7)+2(2x-7) then factor out 2x-7 from both terms, thus: (2x - 7)(x^2 + 2) so there,, :)

**IB Math**

does it involve any figure? if there is none, i think there is some info missing,, like what is the relation of BE to other segments/sides (or where is E located), something like that~

**math**

first, notice that the first three terms, x^2-12x+36, is a perfect square, and can be factored into (x-6)(x-6),, now rewriting the expression, it becomes: (x-6)^2 - 49y^2 (x-6)^2 - (7y)^2 this looks like difference of two squares,, let a = x-6 and b=7y, thus: a^2 - b^2 (a-b)(a...

**geometry**

can you repost your question? or just describe that symbol?

**math**

since it is not factorable, use quadratic formula: x = [-b +- sqrt(b^2-4ac)]/(2a) where a = 9, b=-29, c=34 x = [29 +- sqrt(29^2 - 4*9*34)]/(2*9) x = [29 +- sqrt(841 - 1224)]/18 x = [29 +- sqrt(-383)]/18 thus, the roots are: x = [29 + i*sqrt(383)]/18 ; and x = [29 - i*sqrt(383)...

**math**

merle : 623 hannah: 801 you just have to subtract: 801 - 623 = 178 miles so there,, :)

**college math**

first, there is s-shifting here since e^4t is multiplied to cos(2t). from e^4t, we know that a = 4,, and that L{cos 2t} = s/(s^2 + 4) , therefore: L{e^4t(cos 2t)} = (s-a)/((s-a)^2 + 4) = (s-4)/((s-4)^2 + 4) so there,, :)

**math**

summing pounds: 7+6+8+7 = 28 pounds summing ounces: 2+10+5+9 = 26 ounces since 16 ounces = 1 pound, 26 ounces = 26/16 = 1.625 pounds total wight = 28+1.625 = 29.625 pounds,, therefore, 30 is greater than 29.625, --> i think it's letter A haha alright. :) i just reposted...

**math**

800,000 = 0.8 million --> letter C so there,, :)

**math**

remember, speed(or rate) = distance/time,, therefore, r = 40x3/2.5 --> letter A so there,, :)

**college**

Q = mc(T2-T1) where Q = heat in J, m = mass in kg, c = specific heat capacity in J/(g*K), T = temperature in Kelvin,, **change in temperature can have unit degree Celsius or Kelvin,, thus you can use it interchangeably (what i mean is that the units for c can also be J/(g*C)) ...

**math**

first, convert 8 1/2 to improper fraction: 8 1/2 = 17/2 therefore, (17/2)/(1/2) = (17/2)*(2/1) = 17 strips so there,, :)

**math**

you have to multiply, but first convert the mixed number into improper fraction: 1 3/4 = 7/4 therefore, 8*(7/4) = 14 inches so there,, :)

**math**

you have to multiply, but first convert the mixed number into improper fraction: 1 3/4 = 7/4 therefore, 8*(7/4) = 14 inches so there,, :)

**math**

2 hours = 120 minutes therefore, g = 1.5*120 --> letter C so there,, :)

**math correct or no?**

summing pounds: 7+6+8+7 = 28 pounds summing ounces: 2+10+5+9 = 26 ounces since 16 ounces = 1 pound, 26 ounces = 26/16 = 1.625 pounds total wight = 28+1.625 = 29.625 pounds,, therefore, 30 is greater than 29.625, --> i think it's letter A

**geometry**

first of all, i don't know if there is a figure given in your question,, but if there is not, you have to imagine,, it is composed of a trapezoid EBCD and triangle AED,, therefore, Area,trapezoid = (b1+b2)*h/2 Area,triangle = bh/2 A,trap = (13+15)*18/2 = 252 sq yards A,tri...

**MAT 115**

you need to divide,, but first convert both given fractions to improper fraction: 41 1/2 = 83/2 3 3/4 = 15/4 thus, (83/2)/(15/4) = (83/2)*(4/15) 166/15 = 11 1/15 therefore, 11 pieces and there is 1/15 ft of string left so there,, :)

**algebra**

monthly bill = 10 + 0.15K

**physics**

g = 9.8m/(s^2) *acceleration due to gravity on earth* therefore: W,earth = mg = 42.9*9.8 = 420.42 N = 420. N (if significant figures must be checked) W,moon = mg = 42.9*1.17 = 50.2 N so there,, :)

**Science**

is that "pressure change" or "volume change"? if pressure change, new pressure is one-fifth of the original pressure, or 2/10 = 1/5 if volume change,, at a constant temperature, the new volume becomes five times the original, or 5*5 = 25 cubic inches ..sinc...

**math**

calculating for U: 2=sqrt(2U+7)-sqrt(U) 2+sqrt(U)=sqrt(2U+7) square both sides: 4 + 4*sqrt(U)+ U = 2U+7 transpose all terms not containing squareroot on one side of equation: 4*sqrt(U) = 2U + 7 -4 - U 4*sqrt(U) = U + 3 square both sides: 16U = U^2 + 6U + 9 U^2 -10U + 9 = 0 (U-...

**Science**

note that volume is directly proportional to the temperature at a constant pressure, or: V = kT or V/T = k *Ideal Gas* therefore, if V quadruples, absolute Temp must quadruple also,, so there,, :)

**Science**

is that, "force of 10 lbf"? if it is, pressure is force per unit area, or: P = F/A P = 10 lbf/2 in^2 P = 5 psi (pounds per square inch) so there,, :)

**math**

correct~ :)

**math**

first, count the number of decimal places (number of digits at the right of decimal point,, for example, 0.24 --> 2 decimal places 3.032 --> 3 decimal places 1.00702 ---> 5 decimal places then make this a whole number (no decimal) and divide this by 100..... (the numb...

**physics**

Work is displacement multiplied by force (and it is scalar): W = F*d W = 56 N * 1 m W = 56 J so there,, :)

**6th grade**

simplified energy balance: Q,absorbed + Q,lost = 0 where Q = mc(T2-T1) in which Q=heat in J, m=mass in kg, c=specific heat capacity (which has a definite value for various substances) in J/(kg*C), T=temperature in Kelvin *T2=final temp (the same for both and is usually the unk...

**algebra 1**

distance = rate*time distance = 4*8 = 32 meters therefore, 90-32 = 58 meters BELOW sea level so there,, :)

**algebra 1**

23000/1000 = 23 23*2 = 46 degree-drop therefore, 65-46 = 19 degrees so there,, :)

**8th grade**

(1) c = 3d - 27 (2) 4d + 10c = 120 there are several ways to solve this problem (system of linear equations),, but in this case, we substitution method since in equation (1), variable c is expressed in terms of the other variable d,, we then substitute c from equation (1) to e...

**MATH**

since, it's not factorable, use qudratic formula: x = [-b +- sqrt(b^2-4ac)]/(2a) where a=2, b=34, c=-141 x = [-34 +- sqrt(1156-4*2*(-141)]/(2(2)) x = [-34 +- 2*sqrt(571)]/4 x = (1/2)(-17-sqrt(571)) ; and x = (1/2)(-17+sqrt(571)) so there,, :)

**algebra**

recall that the sum of the interior angles of any triangle is 180 degrees,, thus: 3x + (x+10) + (2x-40) = 180 6x - 30 = 180 6x = 210 x = 35 therefore, the angles are: 3x = 3(35) = 105 x+10 = 35+10 = 45 2x-40 = 2(35)-40 = 30 ..and the smallest angle is 30 degrees so there,, :)

**Math - derivative of f(x) (check)**

do you mean, f(x) = x/(x-1) *equal sign* if so, it's correct. :)

**math**

first, we simplify the function: (x^3-5x^2+6x)/(x^2-9) x(x^2-5x+6)/(x-3)(x+3) x(x-2)(x-3)/(x-3)(x+3) cancel out x-3: x(x-2)/(x+3) thus, the limit as x--> is: 3(3-2)/(3+3) 1/2 so there,, :)

**math**

let x = number of questions answered correctly set up the equation: 2x = 34 then solve: 2x = 34 *divide both sides by 2 to get x x = 34/2 = 17 so there,, :)

**math**

unique solution means the lines intersected at only one point (intersecting lines),, thus lines that do not intersect don not have a solution (parallel lines) if two lines are parallel, then their slopes must be equal,, thus get their slopes by writing them into the form: y = ...

**5 th math**

half means divided by two,, if 8 counters = 1 whole then 8/2 = 4 counters is half. one-third is divided by three,, if 9 counters = 1 whole then 9/3 = 3 counters is one-third. so there,, :)

**5th grade **

half means divided by two,, if 8 counters = 1 whole then 8/2 = 4 counters is half. one-third is divided by three,, if 9 counters = 1 whole then 9/3 = 3 counters is one-third. so there,, :)

**:( math**

24*(3/5) = 14.4 dollars (for stereo equipment) 24-14.4 = 9.6 dollars (money left) 9.6*(1/6) = 1.6 dollars (for lunch) 24-(14.4+1.6) = 8 dollars so there,, :)

**:)**

24*(3/5) = 14.4 dollars (for stereo equipment) 24-14.4 = 9.6 dollars (money left) 9.6*(1/6) = 1.6 dollars (for lunch) 24-(14.4+1.6) = 8 dollars so there,, :)

**math inequalities please check**

your inequalities are right. :)

**math**

24*(3/5) = 14.4 dollars (for stereo equipment) 24-14.4 = 9.6 dollars (money left) 9.6*(1/6) = 1.6 dollars (for lunch) 24-(14.4+1.6) = 8 dollars so there,, :)

**algebra**

when you have a term squareroot (for example sqrt(x))in the denominator, multiply it with itself such that the multiplier is equal to one ( sqrt(x)/sqrt(x) ) to remove the squareroot,, in this problem: 1+(-2/(sqroot 5)) 1+(-2/(sqroot 5))*(sqrt(5)/sqrt(5)) 1+{[-2*sqrt(5)]/5} th...

**science**

density is mass per unit volume: d = m/V therefore: d = 19.5/13 d = 1.5 g/mL so there,, :)

**Algebra. **

..what i did not understand is this one: "ab solve for a", or are you trying to say solve for 'a' in the given equation? if it is: to solve for 'a', transpose all terms to the other side such that 'a' will be left on one side of the equation,,...

**6th grade**

first, write inequality equations using the given statements/description: let x = numerator let x+4 = denominator 1/8 < x/(x+4) *fraction is greater than 1/8 x + 4 < 8x 7x > 4 x > 4/7 x/(x+4) < 1/4 *fraction is less than 1/4 4x < x + 4 3x < 4 x < 4/3 no...

**Math**

first, write inequality equations using the given statements/description: let x = numerator let x+4 = denominator 1/8 < x/(x+4) *fraction is greater than 1/8 x + 4 < 8x 7x > 4 x > 4/7 x/(x+4) < 1/4 *fraction is less than 1/4 4x < x + 4 3x < 4 x < 4/3 no...

**math**

log 2.135 = 0.3294 *just use calculator :)

**MAth**

if the base is 10, log (28) = 1.447 if the base is 2, log(base 2) 8 = x can be written into: 2^x = 8 x = 3 so there,, just use calculator :)

**math**

*i interpreted this in two ways: (1) equation: (11/24)x = 68/24 11x = 68 x = 68/11 (2) equation: 11/(24x) = 68/24 11/x = 68 x = 11/68 so there,, :)

**math**

x = -2 is a vertical line,, since there is no variable y in the equation, x is independent of y, which means, the value of x is constant. to see that it is really a vertical line, get some points: (-2,-1) , (-2,0) , (-2,1) , (-2,2) the slope of this is undefined, the formula f...

**algebra**

* i think your inequality is your because -10 cannot be greater than 7,, anyway, solving for x: 7 < 1-2x < -10 7-1 < -2x < -10-1 6 < -2x < -11 -3 > x > 11/2 *note that when you divide a negative number (here, we divide -2 to all terms to get x), you mus...

**trig**

note that 13pi/12 is also 195 degrees, which can be expressed as difference of two angles, 240 - 45: sin(13pi/12) = sin(195) = sin(240-45) *expanding this, sin(240)cos(45)-cos(240)sin(45) (-sqrt(3)/2)(sqrt(2)/2)-(-1/2)(sqrt(2)/2) (-sqrt(6)/4)+(sqrt(2)/4) therefore: {[sqrt(2)-s...

**math**

combine similar terms (2x4 + 3x3 - 4) + (3x4 - 2x3 - 8) 2x^4 + 3x^4 + 3x^3 - 2x^3 - 4 - 8 *for terms with variables, add their numerical coefficients (or the numbers before them), thus: 5x^4 + x^3 - 12 so there,, :)

**Pre Cal**

g(x)= 1/2(x-1)^3-4 let g(x) = y y = 1/2(x-1)^3-4 *interchange the variables x and y: x = 1/2(y'-1)^3-4 *solve for y': x + 4 = (1/2)(y'-1)^3 2x + 8 = (y'-1)^3 (2x + 8)^(-3) = y' - 1 (2x + 8)^(-3) + 1 = y' or y' = g^(-1)(x) = 1/[2x+8)^3] + 1 so there,...

**science**

first, write the balanced equation: Cl2 (g) + 2Na (s) --> 2NaCl (s) *chlorine gas is diatomic* then, do dimensional analysis to cancel units: g of NaCl = (45.6 g Cl2)*(1 mol Cl2/35.45*2 g Cl2)*(2 mol NaCl/1 mol Cl2)*(58.45 g NaCl/1 mol NaCl) *35.45 g is atomic mass of Cl, b...

**maths**

15 minutes is 15/60 or 0.25 hour (in decimal hour) therefore, 5*4.25 = 21.25 dollars so there,, :)

**maths**

to find distance, use the distance formula: d = sqrt[(y2-y1)^2 + (x2-x1)^2] but first, we look for the points,, let the starting point at the origin (0,0) -- this is (x1,y1) then it traveled 5 miles south (0,-5) and finally, it traveled 11 miles east, thus (11,-5) -- this poin...

**maths**

4000 - 3000 = 1000 (increase) %increase = (1000/3000)*100 = 33.33%

**maths**

since it forms a triangle, use pythagorean theorem: c^2 = a^2 + b^2 where c = 10, a = 4 (the height) and b is the unknown (the base),, therefore: 10^2 = 4^2 + b^2 84 = b^2 b = 2*sqrt(21) = 9.165 ft so there,, :)

**Mat/116 Algebra**

(a) first, represent the unknown with a variable,, *let P = price of amusement park ticket the sign of greater than is > ; greater than or equal to is > with underline (but here i will use >=): P >= 29 (b) if you're given an equation and you need the slope, you...

**algebra**

(1) 7x + 5y = -31 (2) -4x + y = 37 first we choose an equation (either of the two) and represent one of the variables in terms of the other,, in this case we choose (2), and represent y in terms of x: -4x + y = 37 y = 37 + 4x we then substitute this equation to (1): 7x + 5y = ...

**Physics**

acceleration is change in velocity over time, or: a = (v2 - v1)/t where v1 = 0, v2 = 40 m/s and t = 8 s therefore: a = (40 - 0)/8 a = 5 m/(s^2) so there,, :)

**chemistry**

internal energy, U, is the sum heat, Q, and work, W: U = Q + W U = 242 - 193 U = + 49 J >>>sign conventions for U = Q + W: *heat absorbed by the system is (+) *heat released by the system is (-) *work done BY the system is (-) *work done ON the system is (+) *work don...

**geomertyy . **

all four strings must therefore be vertical as well. :)

**Geometry**

since point Y is the midpoint of XZ, XY = YZ. since point Z is the midpoint of YW, YZ = ZW. therefore, XY = YZ = ZW. so there,, i'm not good at writing a paragraph~ :P

**Geometry **

since point Y is the midpoint of XZ, XY = YZ. since point Z is the midpoint of YW, YZ = ZW. therefore, XY = YZ = ZW. so there,, i'm not good at writing a paragraph~ :P

**Math**

transpose all terms with variable y to one side of the equation,, in this case, to the left side: 96y - 432 = 84y + 192 96y - 84y = 432 + 192 *when transposing to other side, their signs become the opposite* 12y = 624 y = 52 so there,, :)

**Math**

a=2a/(a-5) *note: don't cancel the variable a (though it can be canceled since a can be factored from the left side and right side of equation),, a^2 - 5a = 2a a^2 - 7a = 0 a = 0 and a = 7 *notice that if you cancel a, equation becomes: 1=2/(a-5) a - 5 = 2 a = 7 ..in which...

**calculus**

first get its derivative,, recall some techniques on how to derive~ the derivative of this function is: f'(x) = [sqrt(2)]*{3x^2 - [3/(sqrt(x))} substituting the value of x (which is 9): f'(9) = [sqrt(2)]*{3(9)^2 - [3/(sqrt(9))} f'(9) = [sqrt(2)]*(243 - 1) f'(9)...

**algebra**

first, transpose all terms with squareroot on one side of the equation, in this case, on the right side: x - 2 = sqrt(x) then square both sides: x^2 - 4x + 4 = x x^2 - 5x + 4 = 0 (x-4)(x-1)=0 x = 4 and x = 1 *remember that you must check if these values satisfy the given equat...

**Calc**

was it also said that you would treat c as another variable? because in most problems, c is treated as a constant. thus: f'(x) = c g'(x) = c

**Math**

Right. :)

**Math**

to do this, just subtract the similar terms: (f-g)(x) = 5x-2 - (-8x+9) (f-g)(x) = 5x + 8x - 2 - 9 (f-g)(x) = 13x - 11 so there,, :)

**Math**

to do this, just divide: f/g = (4x^2 - 7x)/(x^2 - 3x - 28) since, there is no common factor from numerator and denominator and nothing can be cancelled, f/g = (4x^2 - 7x)/(x^2 - 3x - 28) so there,, :)

**algebra**

since 1/10 was consumed, 9/10 was not used,, therefore: (5/6)*(9/10) = 3/4 so there,, :)

**12th grade**

x-intercept: where y is equal to zero. therefore: 0 = 42x^2 + 28x 0 = x(42x + 28) x = 0 ; and x = -28/42 = -2/3 x-int: (0,0) and (-2/3,0) so there,, :)

**Math - Solving equation (check )**

right. multiply 7 by the denominator, you should get: 7*2sqrt(210t+44t^2) = 210 + 88t 14*sqrt(210t+44t^2) = 210 + 88t then square both sides: 196(210 + 44t^2) = 7744t^2 + 36960t + 44100 8624t^2 + 41160t = 7744t^2 + 36960t + 44100 880t^2 + 4200t - 44100 = 0 44t^2 + 210t - 2205 ...

Pages: <<Prev | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | **14** | 15 | Next>>