Friday

December 2, 2016
Total # Posts: 46,760

**math**

better this time. B is correct

*November 16, 2016*

**Algebra**

If you went from 9|9-8x|=2x+3 to 8x=2x-6 you certainly did not divide by 9 (on BOTH sides)! All absolute-value problems have two possibilities. First, 9(9-8x)=2x+3 81-72x = 2x+3 78 = 74x x = 39/37 Second, 9(9-8x) = -(2x+3) 81-72x = -2x-3 70x = 84 x = 6/5

*November 16, 2016*

**Algebra**

|-4(-2)-8| + |-1-(-2)^2| + 2(-2)^3 |-4(-2)-8| + |-1-4| + 2(-8) |8-8| + |-1-4| - 16 0+5-16 -11

*November 16, 2016*

**Math**

no. 5:9 = ratio of squares:total squares:circles = 5:4

*November 16, 2016*

**Math - OK**

Huh. CDAC is correct. Don't know why I said otherwise. My bad. Sorry.

*November 16, 2016*

**Math**

NO stop guessing and do the math! I even gave you the numbers!

*November 16, 2016*

**Math**

#1 15/50 = 3/10 #2 D is correct #3 70/200 = 35/100 #4 820 * .04 * 3 = ? Looks like you need some review.

*November 16, 2016*

**Calculus**

You should know immediately that 27/4 is not correct, since it does not lie in the interval [0,3]! You want c such that f'(c) = (f(3)-f(0))/(3-0) 3c^2 = 27/3 c = ?3

*November 16, 2016*

**Math**

2(x+12) = 3/2 (2x+12)

*November 16, 2016*

**algebra 1**

16/6

*November 16, 2016*

**math**

44 is the answer, so I suspect a typo. k = 8*110/20 = 44

*November 16, 2016*

**math**

well, 25=5^2 and 9=3^2, so try (5x+3)^2 = ? Note that you will get two answers.

*November 16, 2016*

**MATH**

Odd. It agrees with the formula here http://www.had2know.com/academics/paraboloid-surface-area-volume-calculator.html Better double-check my numbers.

*November 16, 2016*

**MATH**

In cylindrical coordinates, you have z = r^2 r = 2 symmetry allows us to say v = 4?[0,2]?[0,?/2] r^2 * r dr d? = 4?[0,2]?[0,?/2] r^3 dr d? = 2? ?[0,2] r^3 dr = 2? * 16/4 = 8?

*November 16, 2016*

**math**

k = 8*110/20 = 44 I suspect a typo somewhere.

*November 16, 2016*

**Calc**

I think it is true.

*November 16, 2016*

**Algebra**

It is the same as saying that a 0 is picked, either as 1st or 2nd pick: (1/6)(1) + (5/6)(1/5) = 1/3

*November 16, 2016*

**Algebra**

(3x/5-7)+7 Just get rid of the parentheses: 3x/5 - 7 + 7 3x/5

*November 16, 2016*

**math**

(5x+3)^2 = ?

*November 16, 2016*

**Math**

or, to work with smaller numbers, divide by 7 and then multiply by 22.

*November 16, 2016*

**math**

since time = distance/speed, 30/a = 30/b + 2 30/(2a) = 30/b - 1

*November 16, 2016*

**Algebra**

If you add the two equations, you get 12x = 24 because -8y+8y = 0 Now you know x=2, so y=0

*November 16, 2016*

**Algebra**

rewrite #1 and you get 10x-8y=20 2x+8y=4 Now add the two equations and y goes away. Solve for x, then get y.

*November 16, 2016*

**Fibonacci Sequence - malformed**

I assume you mean Un+1 = 3Un + 1/(5Un+3) since no other interpretation makes any sense. But that's not an integer sequence. So, how about fixing your typos, using parentheses, and maybe say U<n+1> to avoid mixing subscripts with numeric values?

*November 16, 2016*

**FLAGPOLE MATH!**

the ratio of shadow_length to height is the same for pole and girl, so s/12 = 4/5

*November 16, 2016*

**ALGEBRA**

13P9 but that is not one of the choices. Typo? However, 1,235,520 = 13P6

*November 16, 2016*

**Math**

actually, it's 1/2 that.

*November 16, 2016*

**Math**

use law of cosines to get the included angle t. Then 20*30*sin(t) = 430

*November 16, 2016*

**Calculus**

this is one of the standard trig integrals. Recall that d/dx sec(x) = sec(x) tan(x) The integral should now be clear.

*November 16, 2016*

**Maths**

There are 100 numbers. So, There are 50 pairs of numbers with sum=202 sum = 20200/2 = 10100

*November 16, 2016*

**math**

T2 and T5 differ by 3d = 6 Now you can easily get d and a, and S16 = 8(2a+15d)

*November 16, 2016*

**Maths**

(a+4d)/(a+d) = (a+13d)/(a+4d) a+d + a+4d + a+13d = 9 AP: a=3/13, d=6/13 T2 = 9/13 T5 = 27/13 T14 = 81/13 Clearly the have a common ratio of 3

*November 16, 2016*

**Math**

14 + 2/3 x = 5/4 x

*November 16, 2016*

**Calculus**

wherever e^x - 3x^2 = 0 That is, where e^x = 3x^2 You might not know just where they are, but you do know that 3x^2 is a parabola with vertex at (0,0). Since e^x is kind of flat near there, you know that for x<0 there will be an intersection. Now the question is, will there...

*November 16, 2016*

**solid geometry**

Here is a good place to start. http://mathcentral.uregina.ca/QQ/database/QQ.09.07/s/juan1.html

*November 15, 2016*

**geometry**

try http://www.volumeofcube.com/sphere-tangent-edges-volume

*November 15, 2016*

**Table of Values**

clearly, y=3 for any values of x.

*November 15, 2016*

**Algebra2**

thank you both

*November 15, 2016*

**Algebra2**

Determine whether the function represents exponential growth or decay. Then find the y-intercept. y=4(5/6)^x

*November 15, 2016*

**precalc**

again? http://www.jiskha.com/display.cgi?id=1479252554

*November 15, 2016*

**Algebra2**

try this site - it shows all the steps http://www.mathportal.org/calculators/polynomials-solvers/synthetic-division-calculator.php

*November 15, 2016*

**Algebra2**

Use synthetic division to find p(3) for p(x)=x^4-2x^3-4x+4 Show steps

*November 15, 2016*

**Algebra2**

is y=1/4x^0.5 a power function. Explain why or why not.

*November 15, 2016*

**Calculus**

f(4) = 8 f(9) = 12 slope of secant = 4/5 f'(x) = 2/?x so, find c such that 2/?c = 4/5

*November 15, 2016*

**Math**

(x+10) + (3x+10) = 76

*November 15, 2016*

**pre calc**

vertical asymptotes at -3,3 zeroes at -4,2,5 multiplicity 3,2,1 hole at x = -1 (x+1) occurs in both top and bottom no horizontal asymptotes http://www.wolframalpha.com/input/?i=((x%2B4)%5E3(x%2B1)(x%E2%88%922)%5E2(x%E2%88%925))%2F((x%2B3)%5E2(x%2B1)(x%E2%88%923))+for+-5%3C%3Dx...

*November 15, 2016*

**Math help**

two weeks for the trip half the distance each week, right?

*November 15, 2016*

**Math**

2(x+y) = 186 xy = 2156 x(93-x) = 2156 44*49 = 2156

*November 15, 2016*

**Algebra**

geez, just use y=x-2 in the first equation: x^2 - x(x-2) + 3(x-2)^2 = 15 3x^2 - 10x - 3 = 0 ...

*November 15, 2016*

**Chemistry**

I have no idea, but I'm sure our chemistry guys will weigh in. In the meantime, I find it hard to believe that you would be given such a question without having studied something like it already. How can you possibly have "no idea" where to start? Check your text...

*November 15, 2016*

**Chemistry**

try google - useful hits right off

*November 15, 2016*

**math**

pi/6 * 30^3

*November 15, 2016*

**Chemistry**

5 times the volume, so 1/5 the molarity. similarly for the 2nd part.

*November 15, 2016*

**Algebra2**

thank you

*November 15, 2016*

**Algebra2**

Which correctly describes the roots of the following cubic equation? x^3-5x^2+3x+9=0

*November 15, 2016*

**math**

3500 * e^(.04*3)

*November 15, 2016*

**Calc**

why not just use x? f(x) = 2secx+tanx f' = 2secx tanx + sec^2x = sec^2(x) (2tanx/secx+1) = secx^2(x) (2sinx+1) critical numbers are where sec^2(x) = 0 -- no solutions there sinx = -1/2 -- x = 7?/6, 11?/6

*November 15, 2016*

**math**

433/(433+424) Actually, that is just the probability that they answered "yes." They may have been lying...

*November 15, 2016*

**Calculus**

typo alert dy/dt at y=2.5 is -1/160, not -1/120

*November 15, 2016*

**Calculus**

When the water is 2.5m deep, the section draining is just a rectangular prism with area 160m^2 and height 1/2 m. So, draining at 1m^3/min, the water level is dropping at a rate of 1/120 m/min When the water is y m deep (y<2), the side cross-section of the pool is a right ...

*November 15, 2016*

**math**

10*6, right?

*November 15, 2016*

**maths need help word problem**

a+b=9 (10b+a)/(10a+b) = 6/5 54/45 = 6/5

*November 15, 2016*

**Algebra**

nope. 9x+3y = -22 has slope -3 better review how to find the slope.

*November 15, 2016*

**Math**

6/(6+7)

*November 15, 2016*

**Math**

come on -- just add them up

*November 15, 2016*

**Math grade 6, Fractions**

64-28=36 stickers that Dan gave Perry 36 is 4/5 of the original amount so, 9 is 1/5 Thus Perry had 45 to start with

*November 15, 2016*

**maths**

the 2nd pole is 20m away the 3rd is 40m and so on

*November 15, 2016*

**Maths**

9,999 and 10,000

*November 15, 2016*

**wisdom'**

and threw up

*November 15, 2016*

**math**

w(3w-2) = 65 what are the factors of 65?

*November 15, 2016*

**Math**

subtracting less means the result will be greater

*November 15, 2016*

**Maths**

Suppose 4 of each color were drawn. That makes 16 balls. The 17th ball would have to be the 5th of one of the colors.

*November 15, 2016*

**math**

if you say so. tan(75/2) = (1-cos75)/sin75 now, 75 = 90-(30/2) so, use the half-angle formulas on that

*November 15, 2016*

**College Algebra**

left: y = (x+4)^3 up: y = (x+4)^3 + 8 scale: y = 0.75((x+4)^3 + 8) = (3/4)(x+4)^3 + 6 = (3/4)x^3 + 9x^2 + 36x + 54

*November 15, 2016*

**Arithmetic**

.20 * 29.50

*November 15, 2016*

**Math**

man - just use the formula! Prt = 4010 * .052 * 4

*November 15, 2016*

**geometry**

see previous post for method.

*November 15, 2016*

**geometry**

well, the central angle is the same as the exterior angle... Or, you have an isosceles triangle with vertex of 60. The interior angles are made up of two of the triangles' base angles.

*November 15, 2016*

**Chemistry**

see the related questions below

*November 15, 2016*

**Algebra**

note that y changes by 2 when x changes by 1.

*November 15, 2016*

**Math**

10096

*November 15, 2016*

**math**

in 4 days, A&B&C did 4(1/24 + 1/36 + 1/48) = 13/36 of the job In the last 3 days, B working alone did 3/36 = 1/12 of the job That left A&B to do 5/9 of the work 1/24 + 1/36 = 5/72, so it took A&B 8 days to do their part.

*November 15, 2016*

**math**

none of the above, that's for sure.

*November 15, 2016*

**Chemistry**

google is your friend. And it's faster than waiting around here.

*November 15, 2016*

**College Calculus**

20 * (1/2)^(t/27)

*November 14, 2016*

**Math : )**

1/6 + 1/3 = 1/2 red or blue 3/7 * 1/2 = 3/14 green 3/14 x = 27 x = 126 21 red 42 blue 27 green

*November 14, 2016*

**Tim**

oh please - just use their definition! f2(x) - f3(x) = (1/8 (x+16)^2-98) - (2x+24) You might want to simplify that to x^2/8 +2x -90

*November 14, 2016*

**Tim**

no idea what you want to do. We could make g(x) = f2(x) - f3(x) or whatever you want to do. What do you mean when you say "this function"?

*November 14, 2016*

**math**

no files here. Surely you can compare two numbers!!???!?

*November 14, 2016*

**Math**

pieces: x x/2 x/2+4 x + x/2 + x/2+4 = 10 2x = 6 x = 3 check: 3 + 1.5 + 5.5 = 10 How did they come up with 2 3/4? I suspect a typo. f(-1/2) = 2(1/4) - 1/4 - 4 = -15/4

*November 14, 2016*

**Geometry**

Pair up the sides. You will find that the three sides of the two triangles match up, so since the two triangles have matching sides, they are congruent: SSS

*November 14, 2016*

**Algebra**

x + 2x+3 = 51

*November 14, 2016*

**maths**

40 spaces, so 41 poles. I think you can gt (c). Figure out how far the nth pole is.

*November 14, 2016*

**maths**

well t wholes is 24/24 So what do you add to 7 to get 24?

*November 14, 2016*

**Math**

and have someone seal the edges tightly with duct tape. Soon your pain will be gone.

*November 14, 2016*

**College algebra**

you have to multiply by 1/2 every 1500 years. So, the fraction remaining after t years is (1/2)^(t/1500) So, after 2800 years, the fraction remaining is (1/2)^(2800/1500) = 2^-1.8667 = 0.2742 = 27.42% Note that 2800 is almost 3000, or two half-lives. At t=3000, 1/2^2 = 1/4 = 0...

*November 14, 2016*

**Math**

Start with T1 which has sides 1 and 1. Its hypotenuse is ?2 Now draw T2, with its base as the hypotenuse of T1, and its other side is 1. T2 has sides ?2 and 1, so its hypotenuse is ?3 Keep drawing new triangles on the hypotenuse, and you will get a spiral figure. Tn has its ...

*November 14, 2016*

**Math checking answers (Calculus Differentials)**

I got the same answers. I hope we're both right!

*November 14, 2016*

**Algebra**

since the flat fee is less than the hourly fee, the more hours, the more pay.

*November 14, 2016*

**Algebra**

since the number of hours worked is the same, of course adding another $50 fee will pay more.

*November 14, 2016*