计算:(1)(1+1/x-1)÷(x/x-1)(2)x^2-4x+4/x^2-4÷ x^2-2x/x+2(3)(a/ab

1个回答

  • [1+1/(x-1)]÷x/(x-1)

    =[(x-1+1)/(x-1)]÷x/(x-1)

    =x/(x-1)÷x/(x-1)

    =1

    (x²-4x+4)/(x²-4)÷(x²-2x)/(x+2)

    =(x-2)²/[(x+2)(x-2)]×(x+2)/x(x-2)

    =1/x

    [a/(ab-b²)-b/(a²-ab)]÷[1+(a²+b²)/2ab]

    =[a²/ab(a-b)-b²/ab(a-b)]÷[2ab/2ab+(a²+b²)/2ab]

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

    =(a+b)/ab×2ab/(a+b)²

    =2/(a+b)

    [(2a-b)/(a+b)-b/(a-b)]÷(a-2b)/(a-b)

    ={[(2a-b)(a-b)]/[(a+b)(a-b)]-b(a+b)/[(a+b)(a-b)]}×(a-b)/(a-2b)

    =(2a²-3ab+b²-ab-b²)/[(a+b)(a-b)]×(a-b)/(a-2b)

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

    =2a/(a+b)

    (a²-b²)/(a²-ab)÷[a+(2ab+b²)/a]

    =[(a+b)(a-b)]/a(a-b)÷(a²+2ab+b²)/a

    =(a+b)/a×a/(a+b)²

    =1/(a+b)