(2x^2y-4xy^2)-(-1/2xy^2+x^2y)其中x=-1,y=2,先化简再求值,好的追加100分

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(2x^2y-4xy^2)-(-1/2xy^2+x^2y)其中x=-1,y=2,先化简再求值,好的追加100分
(2x^2y-4xy^2)-(-1/2xy^2+x^2y)其中x=-1,y=2,先化简再求值,好的追加100分

(2x^2y-4xy^2)-(-1/2xy^2+x^2y)其中x=-1,y=2,先化简再求值,好的追加100分
原式=2x^2y-4xy^2+1/2xy^2-x^2y
=x^2y-7/2xy^2
=1×2+7/2×4
=2+14
=16

(2x^2y-4xy^2)-(-1/2xy^2+x^2y)
=2x²y-4xy²+1/2xy²-x²y
=x²y-7/2xy²
当x=-1,y=2时
原式=x²y-7/2xy²
=(-1)²×2-7/2×(-1)×2²
=2+14
=16

首先展开括号， 得 2x^2y-4xy^2+1/2xy^2-x^2y
移项得 2x^2y-x^2y-4xy^2+1/2xy^2
合并得 x^2y-7/2xy^2
提取xy 得 xy(x-7/2y)
带入值 -2（-1-7）=16

(x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) .(x+y-2)(x+y-2xy)+(xy-1)^2 x-y/x^2+xy除以xy-x^2/x^2y^2-x^4*1/x-y XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2) 1-2/x+y=xy,4y+6x=xy.求xy的解? 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) (x^2+2xy+y^2-4xy)*(x^2-2xy+y^2+4xy) （x^2+xy/x-y)/（xy/x-y)计算 化简:[4xy(x-y)^-1 + (xy^-1 - x^-1y)/(x^-1 + y^-1)] / (x+y)^2 x²-y²+5x+3y+4（x+y-2xy)(x+y-z)+(xy-1）² x-2xy-1+4y² (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 x-y=1,xy=2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 .已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= (x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6