Question

化简[a/(a-b)-(a＾2)/(a＾2-2ab+b＾2)]÷[a/(a+b)-(a＾2)/(a＾2-b＾2)]+1

Answer 1

1)原式=[ab/(a-b)^2]/[ab/(a+b)(a-b)]+1

=(a+b)(a-b)/(a-b)^2+1

=(a+b)/(a-b)+1

=2a/(a-b)

2)化简原式=[2(x-3)-2(x+3)+2x+18]/(x^2-9)

=2(x+3)/(x+3)(x-3)

=2/(x-3)

为整数

则x-3=-2或-1或1或2

x=1,2,4或5