(3x^2+2y^2)2xy

(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) （xy-x^2)乘以(xy)/(x-y) x^2-xy-6y^2+3xy+y+2 计算3xy[2xy-x(y-2)+x-1] 计算：3xy[2xy-x（y-2）+x] （-3x^y+2xy)-( )=4x^+xy （x^2+xy/x-y)/（xy/x-y)计算 x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 已知x-y=4xy，则2x+3xy-2yx-2xy-y xy(xy+1)+(xy+3)-2(x+y+2分之一）-(x+y-1)的平方 (-3分之1xy)的平方×[xy(2x-y)-2x(xy-y的平方)] (x+y)(x-y)-(2xy+3y)平方