# Posts by Helper

Total # Posts: 1,821

**math algebra1**

x = Janet's distance to office 2x - 1 = Lynn's distance to office x + 2x - 1 = 8 3x = 9 x = 3 x = 3 mi from Janet's house to office 2x - 1 = 5 miles Lynn's house to office

*February 28, 2011*

**Algebra 1**

You're welcome :)

*February 28, 2011*

**Algebra 1**

y = height = -16t^2 + 63t + 4 The vertex of this parabola is called the maximum point. Vertex = -b/2a Vertex = -63/(2(-16)) Vertex = t value = 1.96875 So, the maximum value for t seconds is 1.96875 y = height = -16t^2 + 63t + 4 t = 1.96875 y = -16(1.96875)^2 + 63(1.96875) + 4 ...

*February 28, 2011*

**math**

Assuming he spent all his money, x = Money he started with 1/3 x = spent on hat 1/6 x = spent on socks 12 = spent on a tie Total spent = 1/3 x + 1/6 x + 12 Total spent = 2/6 x + 1/6 x + 12 Total spent = 3/6 x + 12 Money he started with - Total spent = 0 x - (3/6 x + 12) = 0 6/...

*February 28, 2011*

**Math 10+**

Or, do you mean 2^(-3) = 1/(2)^3 = 1/8

*February 28, 2011*

**Math 10+**

1/8 = 0.125 x^(0.125)

*February 28, 2011*

**math**

The diagonal of a square forms two 45-45-90 triangles. The sides of a 45-45-90 triangle are in the ratio, a : b : hypotenuse x : x : x(sqrt(2)) The diagonal is the hypotenuse of this 45-45-90 triangle. Side = 7 7 * (sqrt(2)) = ?

*February 28, 2011*

**algebra-Ann edit your problem**

What is ã ?

*February 28, 2011*

**algebra-Edit your problem**

What is ã ?

*February 28, 2011*

**Math/ Trade & Cash discounts**

You're welcome! I hope I'm right. :) The problem is so wordy, so at first, I wasn't sure if more was expected. Good luck!

*February 28, 2011*

**Math/ Trade & Cash discounts**

1. Looks right. 2. I'm not sure why you subtracted the $7000. first. The problem says 0.18 on orders of at least 22,000 units? 22,000 * 3.00 = 66,000 22,000 * 2.82 = 62,040 66,000 - 62,040 = 3,960 rebate 3960/66000 = 0.06 * 100 = 6% discount 3. 30,000 * 3 = 90,000 30,000...

*February 28, 2011*

**Math/ Trade & Cash discounts**

What exactly is your question? You show work and answers for all 4 questions. Are your answers correct? Are you asking for someone to check your work because you don't know if the answers you have listed are correct? You need to ask specific questions.

*February 28, 2011*

**maths**

Is this what you don't understand? 45% = 45/100 = 0.45

*February 28, 2011*

**algebra**

If this is what you mean, cube root = cr (cr(81)) = (cr(27))*(cr(3)) (cr(81)) = 3*(cr(3)) (cr(81)) = 3(cr(3)) This can be written as 81^(1/3) = 3(3^(1/3)) 81^(1/3) = (3^(3/3)*(3^(1/3)) 81^(1/3) = 3^(4/3)

*February 28, 2011*

**Algebra**

(sqrt(xyz))^3 (sqrt(xyz))*(sqrt(xyz))*(sqrt(xyz)) xyz(sqrt(xyz)) This can be written as, ((xyz)^(1/2))^3 = (xyz)^(3/2)

*February 28, 2011*

**geometry**

What is the figure and where are these segments? (AB, BC, AD, CD) located on this figure?

*February 28, 2011*

**algebra**

Find the area of a rectangle if three of its corners are (-0.1,-3.4), (-7.9,-3.4), and (-0.1,6.8). You are given 3 points of the rectangle. You need to find the 4th point. Rectangle ABCD, labeled clockwise from the bottom horizontal segment. A(-0.1, -3.4) B(-7.9, -3.4) C(-7.9...

*February 28, 2011*

**algbra**

drwls gave you the equation above. "You therefore have a horizontal line with equation" y = 18.1 points (-6.2,18.1) and (-3.4,18.1) As drwls said above, "The slope is zero and the y-intercept is 18.1." The slope intercept form of an equation is, y = mx + b ...

*February 28, 2011*

**geometrY**

Shannon, I'm very sorry. The set-up is wrong (1st line), but the rest is correct. I have no idea where I got that first line. http://member.tripod.com/~BDaugherty/GCSEMaths/shapes.html In the picture, the ratio is T/30 = 2/3 3T = 60 T = 20 Your problem, with the corrected ...

*February 28, 2011*

**algebra 2--duplicate problem**

Answered below.

*February 27, 2011*

**algebra 2**

6r^2 + 13rd + 6d^2 (3r + 2d)(2r + 3d)

*February 27, 2011*

**algebra 2**

6r^2 + 13rd + 6b^2 Cannot be factored. I don't think that is the equation. Are you sure you don't have a couple typos?

*February 27, 2011*

**Math(Urgent)**

Yes, your derivative is correct.

*February 27, 2011*

**Mathematics**

y = 1/2 x - 2 In the 2nd column all of the points have x = +6 y = 1/2 x - 2 y = 1/2(6) - 2 y = 6/2 - 2 y = 3 - 2 y = 1 Therefore, none of the choices are correct (since none of the points have y = 1). I think you have a typo because if I use x = -6 y = 1/2 x - 2 y = 1/2(-6) - ...

*February 27, 2011*

**Mathematics**

16 oz = 1 pound 16.5 lbs * 16 oz/lb = 264 oz Each paper = 0.55 oz 264/0.55 = ? number of papers

*February 27, 2011*

**geometrY**

http://member.tripod.com/~BDaugherty/GCSEMaths/shapes.html See the last picture at the bottom of this web page (for a pic of this exact problem). Using ratios, Tree height = T 15/66 = 6.33/T 15T = 512.73 T = 34.182 T = 34.182

*February 27, 2011*

**Calculus**

Correction for above, | = integrate symbol y = x^3 y^3 = x, y = x^(1/3) Using the formula pi | (f(x))^2 - (g(x))^2 dx pi | x^(1/3)^2 - (x^3)^2 dx pi | x^(2/3) - (x^6) dx pi ( 3/5 x^(5/3) - 1/7 x^7 ) When I evaluated from 0 to 1, I got, 16/35 pi

*February 27, 2011*

**Calculus**

| = integrate symbol y = x^3 y^3 = x, y = x^(1/3) Using the formula pi | (f(x))^2 - (g(x))^2 dx pi | (x^3)^2 - x^(1/3)^2 dx pi | (x^6) - x^(2/3) dx pi ( 1/7 x^7 - 3/5 x^(5/3)) When I evaluated from 0 to 1, I got, - 16/35 pi

*February 27, 2011*

**algebra**

Equation passing through the points (2,5) and ( 7,-3) Slope m = (-3 - 5)/(7 - 2) m = -8/5 y = mx + b y = -8/5 x + b Using point, (2, 5) to find b y = -8/5 x + b 5 = -8/5(2) + b 5 = -16/5 + b b = 5 + 16/5 b = 25/5 + 16/5 b = 41/5 y = -8/5 x + 41/5 In the form, y = mx + b b = y-...

*February 27, 2011*

**college algebra**

135 = 12.5(0.2t - 1) + 19t Solve for t

*February 27, 2011*

**math-calc**

As typed, without parenthesis f(x) = x/x + 1 f' = 0

*February 27, 2011*

**ALGEBRA**

http://www.purplemath.com/modules/graphlin.htm I'm not sure of your question. Do you know how to graph an equation? Is it because there are fractions? If because of fractions, convert to decimals and estimate as best you can. Your equation would be, y = -1.6 x + 8.2

*February 26, 2011*

**algebra-Ann please edit your problem**

What is "3ã" ? And please use parentheses if necessary.

*February 25, 2011*

**math**

See link. This exact problem was solved there. http://www.jiskha.com/display.cgi?id=1236980230

*February 25, 2011*

**math**

Please don't repost a question just asked. Be patient for an answer. Tutors volunteer their time and sometimes it can take awhile for your post to be answered. See your original post.

*February 25, 2011*

**college algebra-Ann, edit your problem**

What is "4ã" ? And please use parentheses if necessary.

*February 25, 2011*

**algebra-Mike, edit your problem**

What is "3ã" Please use parentheses if necessary.

*February 25, 2011*

**algebra-Mike, edit your problem**

What is "5ã" Please use parentheses if necessary.

*February 25, 2011*

**algebra-Mike, edit your problem**

What is "3ã" ? Please use parentheses if necessary.

*February 25, 2011*

**math**

3yrs OLDER than his brother, so you would add + 3 B. 2b + 3

*February 25, 2011*

**math**

Which do you think it is? Hint b = brother's age 2b = twice the brother's age

*February 25, 2011*

**math**

If you sketch this you will see a right triangle is formed. a = 8 b = 6 c = hypotenuse Use the Pythagorean theorem c^2 = a^2 + b^2 Solve for c, road to Bobby's house

*February 25, 2011*

**Calculus 1**

x^7 + y^7 = 8xy 7x^6 + 7y^6 y' = 8y + 8x y' 8x y' - 7y^6 y' = 7x^6 - 8y y'(8x - 7y^6) = 7x^6 - 8y y' = (7x^6 - 8y)/(8x - 7y^6)

*February 25, 2011*

**geometry**

Formula for long diameter (vertex to opposite vertex), d = (2 * side length * sin 67.5)/(sin 45) Formula for short diameter (one side to opposite side) d = ((2 * side length)/(sqrt(2))) + side length I'll do short diameter, d = (2 * 48)/(sqrt2)) + 48 d = (96)/(1.4142) + 48...

*February 25, 2011*

**calculus**

Like I said, more than one way to do this. I suggest follow Reiny's way.

*February 25, 2011*

**calculus**

Thanks Reiny. Nicky, depending on your approach, you need to use both the product rule and the chain rule (more than once). It's easy to get lost in this problem. What exactly do you not understand? Have you tried setting the problem up? One approach, start with the ...

*February 25, 2011*

**calculus**

Just making sure. Do you mean e^(8x^4) or e(8x^4) I've never see "e" referred to "exp" on this site, but I haven't been here long.

*February 25, 2011*

**calculus**

What is exp?

*February 25, 2011*

**math**

48a^2 + 4ab - 140b^2 Factor out 4 4(12a^2 + ab - 35b^2) 4(3a - 5b)(4a + 7b)

*February 25, 2011*

**geometry**

What is the figure? Depending on what the figure is, where is AC and BC ?

*February 25, 2011*

**math--To MathMate**

In regards to your reply to the problem that Daniel posted (f'(-pi)). I really appreciate you (and Reiny) taking the time to confirm that my answer was correct. I don't usually answer unless I am absolutely sure an answer is correct (I don't want to give wrong ...

*February 25, 2011*

**calculus**

All the online integration calculators I tried said that this cannot be integrated. Recheck your problem.

*February 25, 2011*

**Math**

80 mg = 0.08 grams 4 tablets x 20mg ea = 80 mg Looks good :)

*February 25, 2011*

**MATH(CALCULUS)**

Thank you so much Reiny.

*February 25, 2011*

**MATH(CALCULUS)**

Did you find f'(x) first? I just read your earlier post and you said you plugged -pi into 12x/(sinx+cosx) . You have to find f' first, then plug in (-pi). The derivative, f' is, (12(x sin x + sin x - x cos x + cos x)/ (sin x + cos x)^2 Then you plug in (-pi) You ...

*February 25, 2011*

**Math**

1 foot = 0.3048 meters 100 = ? meters

*February 25, 2011*

**last question!!need help!!**

Thanks so much MathMath. I did this problem so many times. After all the time I spent on this it's nice to have confirmation that my answer is correct. If Reiny reads this the same goes to you.

*February 24, 2011*

**last question!!need help!!**

f(x)=12x/(sinx+cosx) The derivative, f ' is, (12(x sin x + sin x - x cos x + cos x)/ (sin x + cos x)^2 Now you have to plug in (-pi) for x. I got -12 - 12pi (my post above answer), but, like I said, I did it really quick. It's late so I'm more apt to make a mistake...

*February 24, 2011*

**last question!!need help!!**

Is the answer -12 - 12pi? I did this real quick, and don't have time to post all the work or to double check my work, so I'm not positive this is correct. I can look at this more in the morning or maybe another tutor will answer.

*February 24, 2011*

**last question!!need help!!**

Did you read my post just above yours? In your first post asking this question, the one that MathMate answered 12pi, you had the problem as, f(x)=12x/sinx+cosx find f(-pie) Now you have, f(x)=12x/sinx+cosx find f'(-pie) f and f' are different. f' is the derivative...

*February 24, 2011*

**last question!!need help!!**

I think I see your problem. In prior posts you had, f(x)=12x/sinx+cosx find f(-pie) Now, you have f', the derivative. f'(-pie). Which is it?

*February 24, 2011*

**last question!!need help!!**

Please see your prior post. If you know the answer, why are you asking? Also, it would help if you posted the answer you think it is, then a tutor might have a better understanding of what is maybe being misunderstood.

*February 24, 2011*

**need some help!!!**

From your previous post, which MathMate answered. f(x) = 12x/(sinx + cosx) for -pi calculus-correction - MathMate, Thursday, February 24, 2011 at 9:45pm The required problem was f(-π) = 12(-π)/(0+(-1)) = 12π 12pi is the answer. You have said that this is not the...

*February 24, 2011*

**Algebra 2**

Pasted from previous post by PsyDag, Since it is not an equation, I cannot solve it for you, but I can help you to simplify it. Get rid of the fractions by multiplying everything by 16. I corrected the -1 to +1. x^4 + 6x^3 + 2x^2 + 16 - 9x^4 + 14x^2 - 16 Combine like terms. If...

*February 24, 2011*

**Algebra**

The slope-intercept form of an equation is, y = mx + b m = the slope b = the y-intercept You need to solve your equation for y, for the equation to be in the slope-intercept form. 3y = 2x - 9 Divide both sides by 3, y = 2/3 x - 9/3 y = 2/3 x - 3 Now, the equation is in the ...

*February 24, 2011*

**Math**

L x W x H 18 x 14 x 8 Room Perimeter P = 2W + 2L P = 2(14) + 2 (18) P = 28 + 36 P = 64 Perimeter * Height P = 64, H = 8 Area to paint = 64 * 8 A = 512 sq ft 512 sq ft/256 sq ft paint coverage = gal of paint needed 512/256 = 2 gals per coat 2 gals/coat * 2 coats = ? ttl gals ...

*February 24, 2011*

**math**

Distance, D = Rate, R * Time, T D = y R = 15 fps T = x seconds D = RT y = 15x

*February 24, 2011*

**geometry**

First, you need to graph this triangle. Then, use the distance formula to find the distance between points (length of the sides). Area A = 1/2 bh

*February 24, 2011*

**Math**

Also, I just noticed, Type A contains (????HOW MANY) ounces of oats and (????HOW MANY)ounces of corn per pound. Type B contains (????HOW MANY)ounces of oats and (????HOW ANY)ounces of corn per pound.

*February 24, 2011*

**Math--Shell Missing Info**

Please recheck your problem, your are missing information. Type A and Type B are both oats and corn mixtures. Is this correct? The farmer wants to combine the two feeds so that the resulting mixture has at least (????HOW MANY POUNDS) pounds of oats and at least(????HOW MANY ...

*February 24, 2011*

**math**

x = amount invested at 6% y = amount invested at 8% 0.06x = interest at 0.06 0.08y = interest at 0.08 Solve simultaneously, x + y = 6400 0.08y = 2(0.06x) x = $2560 y = $3840 $153.60 = 6% int $307.20 = 8% int

*February 24, 2011*

**Maths**

A. The circumference of a circle is the actual length around the circle. Circumference C = 2 pi r r = 30, pi = 3.14 C = (2)(3.14)(30) C = 60(3.14) C = 188.4 for 1 lap 6 laps = 6 * C 6 laps = 6 * 188.4 meters 6 laps = ? meters B. P = 2w + 2L w = 37 cm./100 = 0.37 m L = 5.2 m P...

*February 24, 2011*

**S.P**

I = PRT (Interest = Principal*Rate*Time) I = 30,000 * 0.07 * 4 I = ?

*February 24, 2011*

**math !!!! :O**

This exact question was answered earlier today. See link. http://www.jiskha.com/display.cgi?id=1298550296

*February 24, 2011*

**math**

3x^2 y - 5xy + 12x y^2 - 5x y^2 - 4xy 3x^2 y + 7x y^2 - 9xy

*February 24, 2011*

**trig**

360 deg = circle 360/6 = 60 deg 60 deg * pi/360 = 60pi/360 = pi/3 rads

*February 24, 2011*

**Algebra 1**

x = Rate without wind y = Rate of the wind T = D/R 6 = 3000/(x - y) 6(x - y) = 3000 6x - 6y = 3000 5 = 3000/(x + y) 5(x + y) = 3000 5x + 5y = 3000 Solve simultaneously, 6x - 6y = 3000 5x + 5y = 3000 5 *(6x - 6y = 3000)= 30x - 30y = 15,000 6 *(5x + 5y = 3000)= 30x + 30y = 18,...

*February 24, 2011*

**math-Mathmate could you look at please**

I was working on this at the same tiime as you, but I arrived at a different answer. x = amt Tierra had 2x/5 = amt Tierra spent 3x/5 = amt Tierra had left y = amt Alex had 4x/5 = amt Alex spent y - 4x/5 = amt Alex had left z = amt Nico had $40 = amt Nico spent z - 40 = amt ...

*February 24, 2011*

**math**

I = PRT (Interest, I = Principal, P * Rate, R * Time, T P = 30,000 R = 7% = 0.07 T = 4 I = 30,000 * 0.07 * 4 I = 2100 * 4 I = 8400

*February 24, 2011*

**math**

h/-6 >= 5

*February 23, 2011*

**alg readiness**

Or, your could do, Assuming you know that a dollar is 10 dimes, etc. 1.00 = 10 dimes 4.00 = 4 * 10 dimes = 40 dimes 0.60 cents = 6 dimes 4.60 = 40 dimes + 6 dimes 4.60 = ? dimes

*February 23, 2011*

**alg readiness**

3/5 of a dollar = 0.60 (3/5) 4.60/0.10 = ?

*February 23, 2011*

**algebra**

(8.1 x 10^-9) x (4 x 10^2)? There are different ways to approach this problem I would do this problem like this, 8.1 * 4 * 10^-9 * 10^2 32.4 * 10^-7 0.00000324 32.4 with the decimal point moved 7 places to the left (since the exponent is negative)

*February 23, 2011*

**math 117 for bobpursley**

Ally is NOT correct.

*February 23, 2011*

**math**

Distance D = Rate R * Time T R = rate she rowed R + 2 = combined rate (rowing and river current) RT = D (R + 2)*6 = 16 6R + 12 = 16 6R = 4 R = 4/6 = 2/3 = 0.67 R = 0.67 km/hr rowing

*February 23, 2011*

**ALGEBRA**

If you asked this same question yesterday, refer to that post. I know this was answered yesterday, but I search quickly and can't find it.

*February 23, 2011*

**geometry**

Area of square = side s^2 100 = s^2 s = 10 The diagonals of a square bisect each other and meet at 90 degrees. The diagonals of a square bisect its angles. The diagonals of a square are perpendicular. The diagonals of a square are equal. This means that the two diagonals ...

*February 23, 2011*

**math**

Integration of x^2 ln(x^3+2) | = integration symbol | x^2 ln(x^3 + 2) w = x^3 + 2 dw = 3x^2 1/3 dw = x^2 1/3 | ln(w) dw Integration by parts | u dv = uv - | v du u = ln(w) dv = dw du = 1/w dw v = w 1/3 | ln(w) dw = 1/3 ln(w) w - 1/3 | w 1/w dw = 1/3 w ln(w) - 1/3 | w/w dw = 1/...

*February 23, 2011*

**math**

derivative of ln(x^3 + 2) f'(ln(f(x))) = 1/(f(x)) * f'(x) f'(ln(x^3 + 2)) = 1/(x^3 + 2) * 3x^2 f'(ln(x^3 + 2)) = 3x^2/(x^3 + 2) f' = 3x^2/(x^3 + 2)

*February 23, 2011*

**geometry**

A regular octagon has 8 equal sides P = sum of all the sides, or P = number of sides * length of side P = 8 * 9.4 P = ?

*February 23, 2011*

**math**

Volume of sphere, V = 4/3 pi r^3 2123 = 4/3 pi r^3 6369 = 4 pi r^3 1592.25 = pi r^3 1592.25 = (3.14)r^3 507.086 = r^3 r = 7.97432

*February 23, 2011*

**math**

(-3,7), (5,-1) Slope-intercept form of the equation is, y = mx + b m = slope b = y-intercept To find slope, m Slope m = (y2 - y1)/(x2 - x1) m = (-1 - 7)/(5 - (-3)) m = -8/8 = -1 To find y-intercept, b Use either point, (-3,7) and substitute the x and y values in the slope-...

*February 23, 2011*

**algerbra/math**

x = amount Don has "Leo has 1/5 of the amount Don has" Since Don has " x amount", then 1/5 x = amount Leo has

*February 23, 2011*

**algerbra/math**

x = amount Don has "Nadia has 1/2 of the amount Don has" Since Don has " x amount", then 1/2 x = amount Nadia has

*February 23, 2011*

**algerbra/math**

Sky, I've done two examples for you. All your problems are the same. Your turn to try the other problems. Post your answers and I will check them for you.

*February 23, 2011*

**math**

Or maybe the problem is , (?) 7/25 * 360 (no decimal point) = 2520/25 = 100.8 degrees

*February 23, 2011*

**math**

9% = 0.09 0.09 * $245 = $22.05 spent

*February 22, 2011*

**Math**

60% = 60/100 = 6/10 completed 10/10 - 6/10 = NOT completed

*February 22, 2011*

**Math**

Correct ! Good job :)

*February 22, 2011*

**Math**

d = number of DVDs 4d = number of CDs d + 4d = 60 5d = 60 d = ?

*February 22, 2011*