-2x^+xy+y^-6x-y-2

(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) （xy-x^2)乘以(xy)/(x-y) （x^2+xy/x-y)/（xy/x-y)计算 x^2-xy-6y^2+3xy+y+2 因式分解：x×x-xy-2y×y-x-y -2x^+xy+y^-6x-y-2 X平方-XY-6Y平方+2X-Y+1 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 作乘法:(x+y)(x^2-xy+y^2)；(x-y)(x^2+xy+y^2) (x+y-2xy)(x+y-2)+(1-xy)²