Question

计算1/(a-b)-3ab/(a^3-b^3)-(b-a)/(a^2+ab+b^2)的结果为?

Answer 1

1/(a-b)-3ab/(a^3-b^3)-(b-a)/(a^2+ab+b^2)

=[(a^2+ab+b^2)-3ab-(b-a)(a-b)]/(a^3-b^3)

=(2a^2-4ab+2b^2)/(a^3-b^3)

=2(a-b)^2/(a^3-b^3)

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