Question

【(a平方b-ab平方)分之a+b-(a平方-b平方)分之4)】除以(a平方b-ab平方)分之(a-b)平

Answer 1

原式=[(a+b)/ab(a-b)-4/(a+b)(a-b)]×ab(a-b)/(a-b)²

=[(a+b)²-4ab]/ab(a+b)(a-b)]×ab/(a-b)/(a-b)²

=[(a-b)²/ab(a+b)(a-b)]×ab/(a-b)

=[(a-b)/ab(a+b)]×ab/(a-b)

=1/(a+b)