化简x^2y^2+3xy-7x^2y^2-2(5/2xy+1-3x^2y^2) 希望有人可以回答我哦

1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) （xy-x^2)乘以(xy)/(x-y) 计算3xy[2xy-x(y-2)+x-1] 已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y= (x+y-2xy)(x+y-2)+(1-xy)² (x+y)(x-y)-(2xy+3y)平方 计算：(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3 5x^2y/-1/2xy*3xy^2 x^2-xy-6y^2+3xy+y+2