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化简求值(x+y)(x-y)-(x-y)²-6x²y除2y+(2xy)²除(-4xy)其中

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化简求值(x+y)(x-y)-(x-y)²-6x²y除2y+(2xy)²除(-4xy)其中x=-2,y=1/3
(x+y)(x-y)-(x-y)²-6x²y除2y+(2xy)²除(-4xy)
=x²-y²-x²+2xy-y²-6x²-xy
=-6x²-2y²+xy
当x=-2,y=1/3
原式=-24-2/9-2/3
=-24又8/9
再问: 已知x^m=2,x^n=3,求x^3m+2n的值?
再答: 再帮你回答一题,以后采纳后再求助,不要追问新题 x^(3m+2n) =x^3m×x^2n =(x^m)³×(x^n)² =2³×3² =72
再问: 额打错了是减法x^(3m-2n)
再答: x^(3m-2n) =x^3m/x^2n =(x^m)³/(x^n)² =2³/3² =8/9