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Find constants A and B such that (x + 7)/(x^2 - x - 2) = A/(x - 2) + B/(x + 1) for all x such that x ≠ 1 and x ≠ 2. Give your answer as the ordered pair (A,B).

 

If you guys are able to solve this quickly then that would be great!

 Sep 23, 2018
 #1
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This is known as finding the partial fraction expansionx+7x2x2=x+y(x2)(x+1)=Ax2+Bx1

 

x+7(x2)(x+1)=A(x+1)+B(x2)(x2)(x+1)x:x2, 1x+7=A(x+1)+B(x2)x=(A+B)x1=A+B7=A2B

 

B=1A7=A2(1A)=3A23A=9A=3B=13=2x+7(x2)(x+1)=3x22x+1

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 Sep 23, 2018
edited by Rom  Sep 23, 2018

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