2 3 2 3 2 3 2x y+(-4x y)-(-3x y) 2 2 (3x+x-5)-(4-x+7x) 2 2 (8xy-3y)-5xy-2(3xy-2x)12 2 2 2 __ 5(3x y-xy)-(xy-3x y)其中x=2 y=-1算出来

(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+3y-4)(2x-y) 计算（2x-3y)(x+4y)-(3x+y)(x-2y)（2x-3y)(x+4y)-(3x+y)(x-2y) 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) x(x-y)2-(y-x)3 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² (2x+y)(2x-3y)+x(2y+y) 2a(x-y)-4b(x-y) [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 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x (2x-y)(2x+y)-2(3x-4y)(4y+3x) (3x-y)(y+3x)-2(4x-3y)(4x+3y) x^4+x^3y+x^2*y^2+y^3x+y^4分解因式 (x-3y)(y+2x)-(4y-3x)(3x+4y)计算 5/4(x+y)(-x-y)^3*[-4/3(x-y)]*[-3/5(y-x)^2] (x-4y)(2x+3y)-(x+2y)(2y-x) (2x-y)(3x-4y)-2(x-y)(2x-5y)简便运算