1.(2x-3y)(2x+3y)=2.（5x+3y）（3y-5x）3.（x-3y）（-x+3y）=4.（x+y-z）²=

{(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x+y)(2x-3y)=? 结果用幂的形式表示:1.（x-y）^2(y-x)= 2.(x-y)^2(y-)^2= 3.(x-y)^2(y-x)^3= 4.(x-y)^3(y-x)= 1.（（y+2x)(-2x+y)+4(x+2y)^2)/3y 2.（2(x-y)^3-8(x-y）^2(x+y)+6y(x-y)^2）/2（x-y)^2 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² x(x-y)2-(y-x)3 先化简再求值:(x+y)(x-y)+(x^2-2xy+y^2)-(x^2y)^3÷(x^2y)^2,其中x=1,y=2. 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 1.（x+2)^2-(x+y)^32.(x-y)^2-(x-y)^33.(x-y)^2-(y-x)^3 1.(2x-3y)(2x+3y)=2.（5x+3y）（3y-5x）3.（x-3y）（-x+3y）=4.（x+y-z）²= [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x