(3x+2y)(4x-5y)-11(x+y)(x- - 知识问答

(3x+2y)(4x-5y)-11(x+y)(x-y)+5xy,其中x=2分之七,y=-2分之5

1个回答

(3x+2y)(4x-5y)-11(x+y)(x-y)+5xy
=12x²-7xy-10y²-11x²＋11y²＋5xy
=x²-2xy＋y²
=(x-y)²
=(7/2+5/2)²
=6²
=36

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