先化简,再求值:(a+b/a-b)²·2a-2b/3a+3b÷ab/a²-b²,其中a=2,b=-1.
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![先化简,再求值:(a+b/a-b)²·2a-2b/3a+3b÷ab/a²-b²,其中a=2,b=-1.](/uploads/image/z/135300-12-0.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%3A%EF%BC%88a%2Bb%2Fa-b%EF%BC%89%26%23178%3B%C2%B72a-2b%2F3a%2B3b%C3%B7ab%2Fa%26%23178%3B-b%26%23178%3B%2C%E5%85%B6%E4%B8%ADa%3D2%2Cb%3D-1.)
先化简,再求值:(a+b/a-b)²·2a-2b/3a+3b÷ab/a²-b²,其中a=2,b=-1.
先化简,再求值:(a+b/a-b)²·2a-2b/3a+3b÷ab/a²-b²,其中a=2,b=-1.
先化简,再求值:(a+b/a-b)²·2a-2b/3a+3b÷ab/a²-b²,其中a=2,b=-1.
[(a+b)/(a-b)]^2*(2a-2b)/(3a+3b)÷ab/(a-b)(a+b)
=(a+b)^2/(a-b)^2*2(a-b)/3(a+b)*(a-b)(a+b)/ab
=[(a+b)^2/ab]*2/3 其中a=2,b=-1.
=[(2-1)^2/2*(-1)]*2/3
=-1/3