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Enter (A,B,C) in order below if A, B, and C are the coefficients of the partial fractions expansion of (2x^2 + 3x - 5)/(x(x^2 - 1)) = A/x + B/(x - 1) + C/(x + 1).

 Nov 5, 2020
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2x2+3x5x(x21)=Ax+Bx1+Cx+1

multiply both sides by x(x21):

2x2+3x5=A(x1)(x+1)+B(x)(x+1)+C(x)(x1)

Notice that if you set x to equal 0, 1, and -1, respectively, you can cancel out two of the 3 coefficients, which will make it easier to solve. First, set x = 0:

5=AA=5

Now set x = 1:

2+35=2BB=0

Lastly, set x = -1:

235=2C6=2CC=3

Therefore, the answer is (5,0,3)

 Jul 7, 2021

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