化简求值.1)(2xy-y)-(y+yx)其中x=2 y=2 2)5(a^2b-3ab^2)-2(a^2b-7ab^2)其中a=-2 b=-1
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![化简求值.1)(2xy-y)-(y+yx)其中x=2 y=2 2)5(a^2b-3ab^2)-2(a^2b-7ab^2)其中a=-2 b=-1](/uploads/image/z/13390450-34-0.jpg?t=%E5%8C%96%E7%AE%80%E6%B1%82%E5%80%BC.1%29%282xy-y%29-%28y%2Byx%29%E5%85%B6%E4%B8%ADx%3D2+y%3D2+2%295%28a%5E2b-3ab%5E2%29-2%28a%5E2b-7ab%5E2%29%E5%85%B6%E4%B8%ADa%3D-2+b%3D-1)
化简求值.1)(2xy-y)-(y+yx)其中x=2 y=2 2)5(a^2b-3ab^2)-2(a^2b-7ab^2)其中a=-2 b=-1
化简求值.1)(2xy-y)-(y+yx)其中x=2 y=2 2)5(a^2b-3ab^2)-2(a^2b-7ab^2)其中a=-2 b=-1
化简求值.1)(2xy-y)-(y+yx)其中x=2 y=2 2)5(a^2b-3ab^2)-2(a^2b-7ab^2)其中a=-2 b=-1
(2xy-y)-(y+yx)其中x=2 y=2
=2xy-y-y-xy
=xy-2y
=2*2-2*2
=0
2)5(a^2b-3ab^2)-2(a^2b-7ab^2)其中a=-2 b=-1
=5a²b-15ab²-2a²b+14ab²
=3a²b-ab²
=ab(3a-b)
=(-2)(-1)(-6+1)
=-10
第一题好像是0。。。