化简求值：(x+y)(x-y)+(x-y)²-(6x²y-2xy²)÷2y,其中x=-2,y=1/3

显示全部楼层 · 2011-6-11 23:19:32

(x+y)(x-y)+(x-y)2-(6x2y-2xy2)÷2y,其中x=-2,y=1/3
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千问 · 2011-6-11 23:19:32

(x+y)(x-y)+(x-y)2-(6x2y-2xy2)÷2y=(x+y)(x-y)+(x-y)2-2xy(3x-y)÷2y=(x+y)(x-y)+(x-y)2-x(3x-y)=x^2-y^2+x^2-2xy+y^2-3x^2+xy=-x^2-xy=-x(x+y)=-(-2)(-2+1/3)=-10/3...

千问 · 2011-6-11 23:19:32

(x+y)(x-y)+(x-y)2-(6x2y-2xy2)÷2y=x2-y2+x2-2xy+y2-2xy(3x-1)÷2y=2x2-2xy-2x(3x-1)=2x2-2xy-6x2+2x=-4x2-2xy+2x=-2x(2x+y+...

千问 · 2011-6-11 23:19:32

(x+y)(x-y)+(x-y)^2-(6x^2y-2xy^2)÷2y=x^2-y^2+x^2-2xy+y^2-3x^2+2xy=x^2+x^2-3x^2-y^2+y^2-2xy+2xy=-x^2x=-2上式=-4...

千问 · 2011-6-11 23:19:32

原式=x^2-y^2+(x^2-2xy+y^2)-3x^2+2xy
=-x^2-xy
=-x(x-y)
=-10/3...

千问 · 2011-6-11 23:19:32

=x方-y方+x方-2xy+y方-3x方+xy=-x方-xy=-4+2/3=-10/3...