Posted by **Tim** on Friday, April 18, 2008 at 5:48pm.

Below is my problem with my answers. I don't think this is that tough, but I cannot believe that my ABC answer's are a fraction. Did I do this correctly?

Find the unknowns on the right side of the partial fraction.

(x+3)/(x^3+64)=(A)/(x+4)+(Bx+C)/(x^2-4x+16)

x=0

A= (-x^2B-4xB-x+x-4C+3)/(x^2-4x+16)

B= (-x^2A+4xA-x(-16A+x-4C+3)/(x(x+4)

C= (-x^2B-4xB-x^2A+4x+x-16A+3)/(x+4)

- Algebra -
**Anonymous**, Friday, April 18, 2008 at 6:12pm
No, I would not think you should have a fraction.

- Algebra -
**Reiny**, Friday, April 18, 2008 at 6:19pm
I multiplied both sides of your equation by (x+4)(x^2 - 4x + 16) which is really x^3 + 64

x+3 = A(x^2 - 4x + 16) + (x+4)(Bx+C)

this is an identity, so it is true for any value of x.

Let's pick "easy" values of x

let x=-4

-1 = A(48) + 0 ----> A = -1/48

let x=0

3 = 16A + 4C

3 = 16(-1/48) + 4C ----> C = 5/6

let x=1

4 = 13A + 5B + 5C

4 = 13(-1/48) + 5B + 5(5/6)

B = 1/48

Check my arithmetic, my weak point.

## Answer this Question

## Related Questions

- Mat 116 Final - Is it true when the problem says solve x= then it is one number...
- Algebra - Can someone check my algebra answers and help me with the problems I ...
- Algebra II - Solve 4^(x+2)= 160 How would I round this answer to the nearest ...
- math/algebra - Subtract: express your answer in simplest form. 2/5 - y/y-2 ...
- Algebra - Could someone correct my answers and help with the other problems? 1. ...
- Algebra - Could someone correct my answers and help with the other problems? 1. ...
- Algebra II - Find (f+g)(x),(f-g)(x),(f*g)(x), and (f/g)(x) for each f(x) and g(x...
- Math - Can someone correct them 5) Write fraction as a percent 7/8 My answer: 0....
- statistics - Richard has been given a 5-question multiple-choice quiz in his ...
- Algebra - There are two similar triangles XYZ, and ABC. If x = 8, c = 5, and y...

More Related Questions