6x^2y+2xy-3x^2y^2-7x-5yx-4y^2x^2-6x^2y,其中|x+3|+(y-2)^2=0^2表示平方,

1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， 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? 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) 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-6y^2+3xy+y+2 x^2-xy-2y^2+x+7y-6 2x^2+3xy+y^2+x-y-6 x^2+xy-6y^2-3x+6y [x(x^2y^2-xy)-y(x^2-x^3y)]/(2x^2y) [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y x²+xy-2y²-x+7y-6 x²+3xy+2y-x+y-6因式分解 (-x-y)(x^2+xy+y^2) 化简x^-y^/x^-2xy+y^