x^2 y^2 2xy-x^2-y^2-2xy=(x^2__

（xy-x^2)乘以(xy)/(x-y) （x^2+xy/x-y)/（xy/x-y)计算 因式分解x^2-3xy-10y^2=__ (x+y-2xy)(x+y-2)+(1-xy)² (x^2-xy)y÷y-x/xy怎么做? （-3x^y+2xy)-( )=4x^+xy (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) x-y/x²÷x²-2xy+y²/xy*（xy-x²） 作乘法:(x+y)(x^2-xy+y^2)；(x-y)(x^2+xy+y^2) 因式分解：x×x-xy-2y×y-x-y 已知x-y=4xy，则2x+3xy-2yx-2xy-y x^2+xy+x=36,y^2+xy+y=20,求x+y.