Thursday

July 2, 2015

July 2, 2015

Total # Posts: 1,862

**math, if i have correct answer**

Well if you're doing a proving of trigonometric expressions, you only modify or simplify one side of the equation. Usually it's left side of the equation. So after you're done with proving, you should arrive at an answer sin^2 (θ) = sin^2 (θ)
*April 27, 2015*

**Math**

| t - 24 | ≤ 30 There are two cases here: positive and negative: case I: positive t - 24 ≤ 30 t ≤ 30 + 24 t ≤ 54 case II: negative -(t - 24) ≤ 30 -t + 24 ≤ 30 24 - 30 ≤ t -6 ≤ t We get the intersection of these solution: -6 &#...
*April 27, 2015*

**Math 222**

(x - root1)(x - root2) = 0 Substitute the given roots: (x - (-1))(x - (-2)) = 0 Now expand this.
*April 27, 2015*

**algebra**

Substitute the values for x and y to the given equation, and if it equals to 8, then that point is a solution. For instance take the first point (-1,3): 2x + 3y = 8 2(-1) + 3(3) = 8 -2 + 9 = 8 7 = 8 They aren't equal so that means that point (-1,3) is not a solution to the...
*April 27, 2015*

**critical numbers**

I'm assuming that's f'(x) = (x-3)^3 * (x + 4) * (x^2 + 1) instead of f'(x) = (x-3) ^ 3(x + 4)(x^2 + 1) Critical numbers occur at f'(x) = 0 or does not exist. Let f'(x) = 0: 0 = (x-3)^3 * (x + 4) * (x^2 + 1) Will be true if the terms inside the ...
*April 27, 2015*

**Algebra 222**

-5x + 2y = 16 y = 2x + 7 To do substitution, choose an equation and from that equation, choose a variable and express it in terms of the other. Then substitute that expression to the other equation. Here, let's choose the second equation. y = 2x + 7 Then let's choose ...
*April 27, 2015*

**math**

Volume of rectangular prism: V = lwh Substitute the values: V = 6.5 * 2.5 * 4 V = 65 in^3 Since the juice fills 90% of the box's volume, Volume of juice = 0.90 * 65 = ? hope this helps~ `u`
*April 26, 2015*

**Calc 1**

lim [ ln (x)/(sin (5πx)) ] as x → 1 Use L'hopital's rule. Differentiate numerator and denominator separately: lim [ (1/x) / 5π(cos(5πx)) ] as x → 1 Substitute x = 1: = (1/1) / 5π(cos(5π(1))) = 1 / 5π(-1) = -1 / 5π
*April 26, 2015*

**math**

Two points make a line. So what we'll do is get any 2 values for x, and get their corresponding y-value. For instance, take x = 3. Substituting this to the linear equation, y = 1/3x - 4 y = 1/3 * 3 - 4 y = 1 - 4 y = -3 Therefore, a point on the line is (3,-3) Another point...
*April 26, 2015*

**chemistry**

There are symbols which I don't understand in this problem that you typed, like these ¡æ and ¥ÄH¡Æ. But I understand the reactions. :3 We need to find the ΔH for this reaction: N2H4 + H2 ---> 2 NH3 using the data for these reactions...
*April 26, 2015*

**math**

Let tan(θ) = x So that, 2tan^2 (θ) = 3tan(θ) - 1 becomes 2x^2 = 3x - 1 Solving, 2x^2 - 3x + 1 = 0 (2x - 1)(x - 1) = 0 2x = 1 x = 1/2 : first root x = 1 : second root Substitute back tan(θ): tan(θ) = 1/2 θ = tan^-1 (1/2) θ = 26.6 degrees tan...
*April 25, 2015*

**PHYSICS**

Your solution for acceleration is correct, but I don't know why you changed units from m/s^2 to N. They aren't the same units, since Newton is force units. Numerically, it's correct as well. Anyway, now that you have acceleration (which is -10.316 m/s^2), we'll...
*April 24, 2015*

**Physics**

Formula for open-pipe: f = nv / (2L) Formula for closed-pipe: f = (2n-1)v / (4L) where n = harmonic number v = speed L = length of pipe Just substitute the given values to these equations for n = 3. Units in Hz
*April 24, 2015*

**math**

If that's (-3,3) instead of (-3x,3), then the slope is -2. m (slope) = (y2 - y1) / (x2 - x1) m = (-5 - 3) / (1 - (-3)) m = -8 / (1 + 3) m = -8 / 4 m = -2
*April 24, 2015*

**Math 222**

I understood it as [ (2x + 7y) / 8x ] - [ (2x + 5y) / 2x ] + 2 We can combine them as long as their denominators are the same. Their LCD is 8x. For the first term, its denominator is already 8x so it stays the same. For the second term, to make 2x become 8x, we multiply the ...
*April 24, 2015*

**chemistry**

Assuming ideal gas, we use ideal gas law formula: PV = nRT where P = pressure (atm) V = volume (L) n = moles T = absolute temperature (K) R = universal gas constant = 0.0821 L-atm/mol-K At Standard Temperature & Pressure (STP), T = 273 K and P = 1 atm. Xenon has molar mass of ...
*April 23, 2015*

**Physics**

Acceleration is change in velocity over time, or: a = (v2 - v1)/t Initial velocity (v1) and time (t) is given, and final velocity (v2) is zero since it eventually comes to rest. Convert first the initial velocity units to ft/s, then solve for acceleration. Finally, substitute ...
*April 23, 2015*

**Math- Probability Please Help!**

(1) Yes it's 24, because, 4 x 3 x 2 x 1 = 24 ways (2) You'll choose 2 pairs of jeans from 7 pairs. Order of the items does not matter, so we'll use combinations: nCr = n! / ( r! (n - r)! ) Thus, 7C2 = 7! / (2! (7 - 2)! ) 7C2 = 21
*April 23, 2015*

**Math**

(1) Yes :) (2) No, it's not B. slope: m = (y2 - y1) / (x2 - x1) m = (-35 - (-17)) / (5 - 2) m = -18 / 3 m = -6 slope-intercept form: y - y1 = m(x - x1) y - (-17) = -6(x - 2) y + 17 = -6x + 12 y = -6x + 12 - 17 y = -6x - 5 (3) No, it's not A. If the point is reflected ...
*April 23, 2015*

**Heat and properties of matter**

(1) Pressure is force (N) per unit area (m^2): P = F/A P = mg/A P = (5 kg * 9.8 m/s^2) / (0.0001 m^2) P = ? (2) Heat is simply the flow of energy. (3) If there are no more net flow of energy between them. (4) Heat capacity units is J/K. Specific heat capacity units is J/kg-K
*April 23, 2015*

**Math**

nPr = n! / (n - r)! So, 6P3 = 6! / (6 - 3)! 6P3 = (6 x 5 x 4 x 3 x 2 x 1) / (3 x 2 x 1) 6P3 = (6 x 5 x 4) 6P3 = 120
*April 23, 2015*

**Math - Probability**

There are six even numbers from 0 to 10: 0, 2, 4, 6, 8, 10 And there are 11 numbers total. So P(even) = 6/11
*April 23, 2015*

**algrebra**

1 meter = 1000 millimeters So, 1.3 meter * (1000 millimeters / 1 meter) = ? Units are in millimeters.
*April 23, 2015*

**Algebra**

Multiply numerator by numerator, and denominator by denominator: x/5 * y/z = (x*y) / (5*z) = xy / (5z) I guess that's it. `u`
*April 23, 2015*

**Heat and property matter**

density = mass / volume Since mass is constant, when volume is halved, density must be doubled.
*April 23, 2015*

**Heat and property matter**

Its volume.
*April 23, 2015*

**physics**

Acceleration is change in velocity over time: a = (v2 - v1)/t Initial velocity (v1) is given as 63 km/h. Final velocity (v2) is zero, since it came to rest in 40 s (time). Note that we should convert km/h to m/s too. Thus, a = [ 0 - (63 km/h * (1 h / 3600 s) * (1000 m / 1 km...
*April 23, 2015*

**Heat and property matter**

Because pressure is larger at the bottom than at the top.
*April 23, 2015*

**physics**

Acceleration is change in velocity over time: a = (v2 - v1)/t Initial velocity (v1) is given as 63 km/h. Final velocity (v2) is zero, since it came to rest in 40 s (time). Note that we should convert km/h to m/s too. Thus, a = [ 0 - (63 km/h * (1 h / 3600 s) * (1000 m / 1 km...
*April 23, 2015*

**college math**

If it said, 3.32 ÷ 4 * 10 without brackets and written in one line then, yes, your answer is correct. However if it is, 3.32 ÷ (4 * 10) then the answer is 0.083
*April 23, 2015*

**Physics**

Find these values in textbooks or google: Hv = latent heat of vaporization Hf = latent heat of fusion c,water = specific heat of liquid water Formula for energy: Q = m*c*(T2 - T1) Summation of all energy is zero: m,steam*Hv + m,steam(c,water)(T2-100) + m,ice(c,water)(T2-0) + m...
*April 22, 2015*

**Chemistry**

Write the balanced reaction: Ca(OH)2 + 2HCl ---> CaCl2 + 2H2O Then we get the moles of HCl by multiplying the given concentration by the volume. I'm assuming that the given concentration, 0.0704 m, is the molarity: M = n/V n = M*V n = 0.0704 M * 18.2 mL n = 1.28128 mmol...
*April 22, 2015*

**math**

Let x = number of days Let y = height cleared after x days If they can clear 11.5 ft per day, the height cleared in x days is: y = 11.5x
*April 22, 2015*

**calc**

Let x = base of triangle Let y = height of triangle Area of triangle is (1/2) base times height, so A = (1/2)xy 24 = (1/2)xy 48 = xy : eqn(1) If the angle between the two equal sides is 166°, then the remaining angles are: 1/2(180° - 166°) = 7° each In your ...
*April 21, 2015*

**math calc**

It's easier to solve if you draw the figure. If you're not sure what 'angle of elevation' or 'angle of depression' is about, I suggest you read some lectures about it first. In your drawing, you can separate them into two right triangles. One triangle ...
*April 21, 2015*

**6th grade math**

Let n = number of girls Since there are 11 more boys than girls, Let n+11 = number of boys Since the total number of children in the class is 24, girls + boys = total n + n + 11 = 24 2n + 11 = 24 2n = 24 - 11 2n = 13 n = 6.5 girls n+11 = 17.5 boys ...which cannot be, since ...
*April 20, 2015*

**Chemistry**

If the stoichiometric coefficients are multiplied by some number, then the value for ∆H (in kJ/mol) is also multiplied by that number. We got earlier the ∆H formation for CO with fraction stoichiometric coefficients: C + 1/2 O2 ---> CO ; ∆H = -110.4 kJ/mol...
*April 20, 2015*

**Chemistry**

∆H for what reaction...? Write the balanced reactions: C + O2 ---> CO2 ; ∆H = -393.7 kJ/mol C CO + 1/2 O2 ---> CO2 ; ∆H = -283.3 kJ/mol CO If the problem asks for ∆H of formation for CO, we can make the second reaction become: CO2 ---> CO + 1/2...
*April 20, 2015*

**Algebra**

Represent the unknowns: Let x = one piece Since according to the problem, the other piece is 5 times as long as the first one, Let 5x = other piece Since their total length must be 24 ft, x + 5x = 24 6x = 24 x = 24/6 x = 4 ft. 5x = 20 ft.
*April 20, 2015*

**Science**

One of the formulas for uniformly accelerated motion (UAM): h = vo*t - (1/2)gt^2 Ball falls freely, so initial velocity (vo) is zero: h = 0 - (1/2)(-9.8)(0.5^2) h = 1.225 meters Since we're looking for the terminal velocity (vf) we can use the formula, vf^2 - vo^2 = 2gd vf...
*April 20, 2015*

**Algebra**

Let x = Meg's age According to the problem, Jill is 2 years younger than Meg: Let x - 2 = Jill's age And it was also said that Beth is half as old as Meg: Let (1/2)x = Beth's age
*April 20, 2015*

**Algebra**

Let x = suggested amount of donation If b is the number of bracelets given away, and every person who makes the suggested donation amount will be given one bracelet, then b is also the number of people donated. Therefore, the total collected amount is the number of people ...
*April 20, 2015*

**Science (Chemistry)**

"Like dissolves like" is a general rule in solubility. Water is a polar molecule. Its structure is not symmetric, and there is polarity between its elements that compose it - the electronegativity difference between H and O is significantly large. Ionic molecules are...
*April 20, 2015*

**Math**

No it's not 8. But you're almost correct, you just forgot to divide it by 2. :) From your solution, p = 2l + 2w 30 = (2 * 11) + 2w 30 = 22 + 2w Put the 22 (from the right side of equation) to the left side, but by doing so, you must change its sign to its opposite. It...
*April 20, 2015*

**algebra**

Let x = width Let y = length Area of rectangle is length x width, so A = xy 912 = xy Perimeter of rectangle is 2*(length + width), so P = 2(x + y) 124 = 2(x + y) 62 = x + y Now that you have two equations tow unknowns, we can solve for x and y. From the second equation, we can...
*April 20, 2015*

**physics**

P = ρgh where P = pressure (in Pa) g = acceleration due to gravity = 9.8 m/s^2 h = height (in meters) Note that 1 bar = 100000 Pa. Substituting, 100000 = (600)(9.8)(h) h = ? Hope this helps~ `u`
*April 19, 2015*

**Redox Reaction**

Write the redox reaction: Mn2+ + BiO3- --→ Bi3+ + MnO4− Balance this redox reaction. Write first the half-reactions: Reduction: BiO3- ---> Bi3+ (charge is changed from 5+ to 3+) Oxidation: Mn2+ ---> MnO4- (charge is changed from 2+ to 7+) Balance them by ...
*April 19, 2015*

**Algebra (check my work?)**

1. Yes 2. Yes 3. Let n = number of 4th grade swimmers The ratio of 4th grade swimmers to the total swimmers is 5:16 or 5/16. The total number of swimmers is 80. Therefore, n/80 = 5/16 If you solve this, you'll have n = 25 swimmers (4th grade) hope this helps~ `u`
*April 17, 2015*

**pre-calc - JAI**

Sn = n(1+3n)/2 Therefore, S1: 2 = 1(1 + 3(1))/2 S2: 2+5 = 2(1 + 3(2))/2 S3: 2+5+8 = 3(1 + 3(3))/2 They are all true/equivalent for S1, S2, and S3.
*April 17, 2015*

**math**

If you want an aquarium in shape of a cube with volume of 8000, then use the formula for volume of cube to find the length of one side: V = s^3 where s = side length Substitute, 8000 = s^3 s = cuberoot(8000) s = 20 inches Well, if you have to draw this on a graphing paper, you...
*April 17, 2015*

**pre-calc**

It's difficult to show Gaussian elimination process here. But the answers should be, x = 1, y = -4 and z = -2
*April 17, 2015*

**phyiscs**

Modified/simplified continuity equation: S1*v1*ρ1 = S2*v2*ρ2 where S1 and S2 = entrance and exit cross-sectional area v1 and v2 = entrance and exit velocity ρ1 and ρ2 = initial and final density Assuming density of water is constant, we can cancel ρ1 ...
*April 16, 2015*

**Science**

Let's have some definitions: Element - the simplest substance made up of one type of atom that cannot be broken down by any chemical means. It can be converted to other elements by nuclear methods, though. Examples are Na, Ca, Mg. Molecule - group of atoms bonded together...
*April 16, 2015*

**Math**

Separate them as such: 6x + 5y = 7x + 3y and 7x + 3y = 2(x + 6y - 1) Simplify both equation: Eqn(1): 6x + 5y = 7x + 3y 6x - 7x = 3y - 5y -x = -2y x = 2y Eqn(2): 7x + 3y = 2(x + 6y - 1) 7x + 3y = 2x + 12y - 2 7x - 2x = 12y - 3y - 2 5x = 9y - 2 We can multiply Eqn(1) by -5 so ...
*April 16, 2015*

**physics class**

Pressure is force (in Newton) per unit area (in m^2): P = F/A The force here is the weight of the ball, so we must find first the weight of the ball: W = mg where m = mass (kg) g = acceleration due to gravity = 9.8 m/s^2 Substitute the values: W = 5 * 9.8 W = 49 N Therefore ...
*April 16, 2015*

**analytical geometry**

Use distance formula: d = sqrt[(y2 - y1)^2 + (x2 - x1)^2] Their distances from one point to (-3,p) must be the same, so sqrt[(-1 - p)^2 + (7 - (-3))^2] = sqrt[(-4 - p)^2 + (4 - (-3))^2] Square both sides: (-1 - p)^2 + (7 + 3)^2 = (-4 - p)^2 + (4 + 3)^2 1 + 2p + p^2 + 100 = 16...
*April 16, 2015*

**math**

There are a lot of ways doing these. Mine might be a long way, there might be a shorter way. Anyway, let the contents of each gallon be represented in this format: (12-gallon bucket) - (7-gallon bucket) - (6-gallon bucket) Fill the 12-gallon bucket. Leave the others empty. So...
*April 16, 2015*

**Math**

(1) In arithmetic sequence, we just add the common difference, d = 0.25, to a term to get the next term. Therefore, a1 = 16.5 a2 = 16.5 + 0.25 = 16.75 a3 = 16.75 + 0.25 = 17.0 ...and so on. (2) General formula for arithmetic sequence: an = ao + (n-1)d where an = nth term ao = ...
*April 16, 2015*

**Math**

F = S/w
*April 16, 2015*

**math plz help**

Yes, both are correct. `u`
*April 15, 2015*

**ALGEBRA 2 (LOGARITHMIC FUNCTIONS)**

For the next questions, they are all solved with the same method. So I'll guide you to solving #1, then try solving the others by following these steps. We need to find an equation in the form y = ab^x that passes through the points (1,6) and (2,36). What we'll do is ...
*April 15, 2015*

**ALGEBRA 2 (LOGARITHMIC FUNCTIONS)**

I'll solve for the first five problems. You have to recall some laws of exponents for these. (1) 3^(x+1) = 27^(x+3) Note that we can rewrite 27 as power of 3: 27 = 3^3. Thus, 3^(x+1) = (3^3)^(x+3) You can distribute the '3' in 3^3 to (x+3). 3^(x+1) = 3^(3(x+3)) 3^(...
*April 15, 2015*

**Algebra 2**

(a) "Z" is distinctly different than the other: I think that means you have to count both of them, as if they're different letters. There are five letters in total. Therefore, 5! = 120 ways (b) "Z" is repeated twice in the word FUZZY. Thus, 5! / 2! = 60...
*April 15, 2015*

**math -check**

Yes, all the equations you wrote are correct. :) I don't know what window setting means too, and I don't have a graphing calculator. But I think window setting looks like in table (rows,columns) format? I'm not really sure. ^^;
*April 15, 2015*

**Math**

Yes it's B. This is another example of conditional probability. Note that there are four vowels here: U, I, O, E. And there are six letters total. So, P(vowel) = 4/6 Then you spin again. The probability of getting a P: P(P) = 1/6 Thus, P(vowel, then P) = 4/6 * 1/6 = 4/36...
*April 15, 2015*

**Math**

No it isn't. It was said that time varies inversely as the rate: t = k/r where t = time (hours) r = rate (mph) k = some constant If we solve for the constant, k, k = r*t and this k is the same for all. Therefore if we have two different values for time and rate, r1 * t1 = ...
*April 15, 2015*

**Math**

Mass, m, is varies inversely as acceleration, a: m = k / a where k some constant. since f is the constant of variation, we substitute f for k: m = f / a
*April 15, 2015*

**integral**

Well the derivative of sec(x) = sec(x) tan(x) dx, as it's one of the formulas usually memorized. So the integral of sec(x) tan(x) dx = sec(x). But if you want a longer method, we let sec(x) = 1/cos(x) and tan(x) = sin(x) / cos(x). Substituting, ∫ sec(x) tan(x) dx &#...
*April 15, 2015*

**Precalculus**

Yeah, you have to draw two different triangles for them. It's easier to solve this if you draw them. Anyway, we let arcsin(8/17) be equal to some angle, A. And we let arctan(4/3) be equal to some angle, B. In your drawing of two triangles, label these angles as A and B. We...
*April 15, 2015*

**chemistry**

At STP, T = 0 C or 273 K and P = 1 atm or 101.325 kPa. Assuming the gas ideal, we can use the formula: P1 * V1 / T1 = P2 * V2 / T2 where P = pressure V = volume T = absolute temperature (in K) subscripts 1 and 2 = initial and final properties respectively substituting, 103 * 5...
*April 15, 2015*

**calculus (steps and explanation plz)**

y'' = 6x Integrate: y' = 3x^2 + c1 Since it was said that it has a horizontal tangent at (1,1), then we let y' (the slope) be equal to 0: 0 = 3x^2 + c1 0 = 3(1)^2 + c1 0 = 3 + c1 c1 = -3 Integrate y' further (and substitute c1 = -3): y' = 3x^2 - 3 y = x...
*April 15, 2015*

**math word problems**

Raul's appointment started at 9:30 AM according to the problem: Raul - 9:30 AM After 17 minutes, Timothy arrived. That is, at 9:47 AM. But it was said that this time is 8 minutes BEFORE his actual appointment. Therefore, we add 8 minutes to it: Timothy - 9:55 AM Tyson'...
*April 15, 2015*

**SCIENTIFIC NOTATION**

What we'll do is divide 1.3 x 10^8 by 8.8 x 10^5: 1.3 x 10^8 / 8.8 x 10^5 We can rewrite 1.3 x 10^8 such that the exponent of 10 is 5. To do this, move the decimal point 3 places to the right. Why 3 places? It's because 8-5 = 3: 1.3 x 10^8 = 1300 x 10^5 Then, 1300 x 10...
*April 15, 2015*

**math plz help**

Well it's a conditional probability. You have to multiply the probability of the first event to the probability of the second event for this kind of problem. If the question asked for the probability of choosing a red OR a blue marble, then their probabilities are added. ...
*April 15, 2015*

**math plz help**

Total marbles = 43 P(red) = 8 / 43 Since it was replaced, the total number of marbles is the same for the second choosing of marble. P(blue) = 12 / 43 Probability of getting a red, then a blue: 8/43 * 12/43 = 96/1849 (letter D)
*April 15, 2015*

**ALGEBRA PLSSSSSS**

To get the inverse, what you'll do is: (1) let f(x)=y, and replace x with y and y with x: f(x) = (8 - 2x)^2 y = (8 - 2x)^2 x = (8 - 2y)^2 (2) solve for y, and substitute back the y=f(x): x = (8 - 2y)^2 sqrt(x) = 8 - 2y sqrt(x) - 8 = -2y y = (sqrt(x) - 8) / (-2) y = (8 - ...
*April 15, 2015*

**geometry/trig**

Let x = original side length (ladder-wall) Let y = original side length (ladder-floor) Well yeah. The new length of the side of the triangle (where ladder touches the wall) is x - 8. The new length of side of triangle (where ladder touches the floor) is y + 16. Of course, y is...
*April 15, 2015*

**math**

Let x = length Let 3/4x = width Area of rectangle is length times width. A = l * w Substituting: 432 = x (3/4x) Solve for x: 432 = (3/4) x^2 x^2 = 432 * 4/3 x^2 = 576 x = 24 ft. (length) 3/4x = 18 ft. (width) hope this helps `u`
*April 15, 2015*

**Math**

1. Not it's actually in Quadrants II and IV. In Q I and III, the coordinates of the point have the same sign. For instance, Quadrant I: (2,4) Quadrant III: (-1,-3) 2. Yes that's right. `u`
*April 14, 2015*

**PHYSICS1**

There's a problem similar to this. I'll just repost it here: Range of projectile formula: R = vo^2 sin(2θ) / g where θ = angle vo - initial velocity g = acceleration due to gravity = 9.8 m/s^2 substitute the values to get the range: R = (18^2) * sin(2*75°...
*April 14, 2015*

**physics**

Range of projectile formula: R = vo^2 sin(2θ) / g where θ = angle vo - initial velocity g = acceleration due to gravity = 9.8 m/s^2 substitute the values to get the range: R = (18^2) * sin(2*75°) / 9.8 R = ? Make sure your calculator is in Degrees mode, not ...
*April 13, 2015*

**chemistry**

You have to have the following values. These can be found in google or in textbooks: *specific heat capacity of ice (c,ice) in J/g-K *latent heat of fusion for water (Hf) in J/g *specific heat capacity of water (c,water) in J/g-K Then substitute them in the summation of all ...
*April 13, 2015*

**Math**

A. Yeah, almost. :) d = rt Since d = 72 miles and t = 1.5 hours or 90 minutes, 72 = 1.5r (if you want r to have units in miles/hour) 72 = 90r (if you want r to have units in miles/minute) B. 72 = 1.5r r = 72/1.5 r = 48 miles/hour 72 = 90r r = 72/90 r = 0.8 mile/min
*April 13, 2015*

**Math 1**

Let x = width Let x + 6 = length Area of rectangle is just width x length. Thus, A = w * l 16 = x(x+6) 16 = x^2 + 6x x^2 + 6x - 16 = 0 Factor: (x + 8)(x - 2) = 0 x = -8 (extraneous root since dimensions cannot be negative) x = 2 inches (width) x+6 = 8 inches (length) hope this...
*April 13, 2015*

**Physics**

Use the formula to get the time: x = vo,x * t where x = horizontal distance vo,x = initial horizontal velocity t = time 47.9 = 12 * t t = 47.9 / 12 t = 3.99 s Then use this formula to get the height of cliff: h = vo,y * t - (1/2)gt^2 where h = height vo,y = initial vertical ...
*April 13, 2015*

**Math**

This problem is similar to the one you posted before. Take two points. For instance, the first two points, (0,1) and (1,4). Get the slope: m = (y2 - y1) / (x2 - x1) m = (4 - 1) / (1 - 0) m = 3 / 1 m = 3 slope-intercept form: y - y1 = m(x - x1) y - 1 = 3(x - 0) Just simplify ...
*April 13, 2015*

**Math**

To do this, just add the numerical coefficient of the variable x. The numerical coefficient is the number before the variable. In this case, its 1/2 in the term 1/2x, and 2/3 in the term 2/3x. (1/2)x + (2/3)x = (3/6)x + (4/6)x = (3 + 4)/6 x = (7/6)x
*April 13, 2015*

**Math**

I will let n = x. Take two points. For instance, the first two points, (3,2) and (4,1). Get the slope: m = (y2 - y1) / (x2 - x1) m = (2 - 1) / (3 - 4) m = 1 / -1 m = -1 slope-intercept form: y - y1 = m(x - x1) y - 2 = -1(x - 3) y - 2 = -x + 3 y = -x + 3 + 2 y = -x + 5 hope ...
*April 13, 2015*

**science**

*sorry, I mean 4.5 / 129.5 = 3.47 % v/v
*April 13, 2015*

**science**

Add the volumes together: V,total = 125 + 4.5 = 129.5 m^3 Since alcohol is 4.5 m^3, the v/v % is V,alcohol / V,total = 4.5 / 129.5 * 100 = 3.6 %
*April 13, 2015*

**chemistry**

I see. No, the 12.5 g shouldn't have any denominator units. The given was only 12.5 g NaOH, and this is the mass of NaOH. You should write, [ 12.5 g NaOH * (1 mol NaOH / 40 g NaOH) ] / [ 625 mL * (1 L / 1000 mL) ] = 0.500 M Sorry for the late reply. Hope this helps~ `u`
*April 13, 2015*

**chemistry**

If you mean that the 12.5 NaOH is 12.5 grams of NaOH, then your answer and solution are correct. :)
*April 13, 2015*

**math**

Let alpha = a Let beta = b Because it's easier to type a and b, than copy-pasting alpha and beta symbols. Anyway, recall that for a quadratic equation in the form y = ax^2 + bx + c The sum and product of the roots can be determined as such: y = x^2 - (sum)x + (product) Of ...
*April 12, 2015*

**PRE - CALCULUS**

Yes it's D.
*April 12, 2015*

**Math**

5 ft : 135° = x ft : 360° 5/135 = x/360 x = 40/3 ft This is the whole length of the circle or the circumference. To get the radius, C = 2πr r = C / 2π r = 40/3 / (2*3.14) r = 2.12 ft
*April 12, 2015*

**MATH**

Why is that? Anyway, let's solve for y. I'll multiply the first equation by -2 instead of 2: (5x - 4y = -3) * -2 ---> -10x + 8y = 6 (2x + 7y = 5) * 5 ---> 10x + 35y = 25 Add them together: -10x + 8y = 6 10x + 35y = 25 ---------------------- 43y = 31 y = 31/43 Now...
*April 12, 2015*

**MATH**

You're doing the elimination method right. :) But there's just some errors in multiplying. In your first equation (5x - 4y = -3), you multiplied it by 2. 5x * 2 = 10x, yes that's right. -4y * 2 = -8y, not -12y as you've typed. -3 * 2 = -6, not 6 as you've ...
*April 12, 2015*

**Physics**

We use the formula: h = vo,y*t - (1/2)gt^2 where h = height vo,y = initial vertical velocity t = time g = acceleration due to gravity = 9.8 m/s^2 Since there is no vertical velocity involved, vo,y = 0. If that's not very clear, we can say that vo,y = vo*sin(angle). But the...
*April 12, 2015*

**Physics**

For the horizontal: x = vo,x * t where x = horizontal distance vo,x = initial horizontal velocity t = time x = 1100 m/s * 0.32 s x = 352 m For the vertical: h = vo,y * t - (1/2)gt^2 where h = height vo,y = initial vertical velocity (which is zero) g = acceleration due to ...
*April 12, 2015*

**WORD PROBLEM HELP**

Volume of a cylinder: V = π(r^2)(h) where π = 3.14 r = radius h = height I think this is just trial and error. For instance, take r =2 and h=6: V = π(2^2)(6) V = 3.14 * 4 * 6 V = 75.36 m^3 This is one that satisfies the requirements. Just take a value of r and h...
*April 12, 2015*