计算：(3xy)^2*(x^2-y^2)-(4x^2y^2)÷8y^2+9x^2y^4快,急

计算：3xy[2xy-x（y-2）+x] 计算3xy[2xy-x(y-2)+x-1] （x^2+xy/x-y)/（xy/x-y)计算 x-y/xy-y^2计算 计算：3xy(x²y-xy²+xy)-xy²(2x-xy+2x） 计算(-xy)(x+2x²y) 计算（xy-y^2)÷x-y/xy 计算：5xy^2-[3xy^2-(4xy^2-2x^2y)]+2x^2y-xy^2 计算:(x^2-2xy)/(x^2-3xy+2y^2)-(xy+y^2)/(x^2-y^2) 计算：(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3 计算2x*(-3xy)²(-x²y)³ xy（2x+y）^2计算 计算3y/(2x+2y)+2xy/x^2+xy 计算(3x^3y-x^2y+1/2xy)÷(-1/2xy） 计算：2x+2y分之3y + x²+xy分之2xy 计算：3y/(2x+2y) +2xy/x²+xy 计算 (21xy^3-7x^2y^2+28x^3y)÷(-7xy) 计算:2x^2y(-2xy^2)+(2xy)^3(-xy^2)^2