When you are dealing with partial fraction decomposition with a repeated factor, in this case, you want something of the form
A / (2x+3) + B / (2x + 3)^2
Where A and B are numbers. You may ask: why not an Ax+B in the numerator on the second fraction, but you already have that, that's your original problem. So in this case, given the numerators, we have
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When you are dealing with partial fraction decomposition with a repeated factor, in this case, you want something of the form
A / (2x+3) + B / (2x + 3)^2
Where A and B are numbers. You may ask: why not an Ax+B in the numerator on the second fraction, but you already have that, that's your original problem. So in this case, given the numerators, we have
A(2x+3) + B(1) = 2x
2Ax + 3A + B = 2x
2Ax = 2x
3A+B = 0
2A = 1
3A + B = 0
A = 1/2
3(1/2) + B = 0
B = -3/2
So your partial fraction decomposition becomes
(3/2) / (2x + 3) - (3/2) / (2x+3)^2
4x^2 + 12x + 9 = (2x+3)^2
so the partial fraction would look like this:
a/(2x+3) + b/(2x+3)^2 because the denominator is a perfect square.
= [a(2x+3) + b]/(2x+3)^2 so now you need only consider the numerator.
2ax + 3a + b = 2x -->
2a = 1 and 3a + b = 0 -->
a = 1/2 and thus b = -3/2
The partial fraction becomes
(1/2)/[2x+3] - (3/2)/[2x+3]^2