# I can't seem to do this with partial fractions

#### skyturnred

1. The problem statement, all variables and given/known data

$\frac{x}{(x+4)^{2}}$

2. Relevant equations

3. The attempt at a solution

I make the integrand equal to the following:

$\frac{A}{(x+4)}$+$\frac{Bx+C}{(x+4)^{2}}$

Then after finding a common denominator I get

x = A(x+4)$^{2}$+(Bx+C)(x+4)

But that cannot be possible because when you set x=-4, you get -4=0. Any help please?

Also if you have ANY tips whatsoever about partial fractions please tell me them!

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#### SammyS

Staff Emeritus
Homework Helper
Gold Member
1. The problem statement, all variables and given/known data

$\frac{x}{(x+4)^{2}}$

2. Relevant equations

3. The attempt at a solution

I make the integrand equal to the following:

$\frac{A}{(x+4)}$+$\frac{Bx+C}{(x+4)^{2}}$

Then after finding a common denominator I get

x = A(x+4)$^{2}$+(Bx+C)(x+4)

But that cannot be possible because when you set x=-4, you get -4=0. Any help please?

Also if you have ANY tips whatsoever about partial fractions please tell me them!
Algebra check:

$\displaystyle\frac{x}{(x+4)^{2}}=\frac{A}{(x+4)}+ \frac{Bx+C}{(x+4)^{2}}$

Multiplying by (x+4)2 gives:

$\displaystyle x=A(x+4)+Bx+C$

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