x^2+xy-2y^2-x+7y-6急用 因式分解

x^2+xy-2y^2-x+7y-6急用 因式分解 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) x^2-xy-2y^2+x+7y-6 x²+xy-2y²-x+7y-6 X2+2XY+y2+x+y等于什么?急用 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 (-x-y)(x^2+xy+y^2) 已知X+y=6,xy=7 求x^2y+xy^2=已知X+y=6,xy=7 x^2y+xy^2 化简x^-y^/x^-2xy+y^ 2*(x-y)²(y-x)(xy) 因式分解:8(x-2y)-x(7x+y)+xy. 化简求值x-4y/2x-7xy+3y×x-2xy-3y/2x+3xy-2y÷3x-6y/4x-4xy+y,其中：x=1999,y=-1 （x^2+xy/x-y)/（xy/x-y)计算 (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， x^2-xy-6y^2+3xy+y+2 3y/x*x-y*y+x/x*x-2xy+y*y+6y*y/x*x*x-x*x*y-xy*y+y*y*y等于多少? x²y－3xy²+2yx²－y²x,急用!