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先化简,在求值:2(x-y)(x+y)-(2x-y)(x+2y),其中x=0.25,y=-4
人气:281 ℃ 时间:2019-10-17 01:46:43
解答
2(x-y)(x+y)-(2x-y)(x+2y),
=2X^2-2Y^2-(2X^2+3XY-2Y^2)
=-3XY,
=-3*1/4*(-4)
=3.
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