计算：(x^2-9y^2)(x^2+3xy+9y^2)(x^2-3xy+9y^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) （x^2+xy/x-y)/（xy/x-y)计算 计算3xy[2xy-x(y-2)+x-1] 计算：3xy[2xy-x（y-2）+x] x-y/xy-y^2计算 计算：(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3 用公式计算(2y-3x)(4y²+6xy+9x²﹚ 计算：（x^2-y^2/xy)^2/(x+y)^2*(x/x-y)^3 计算3x[xy-2x(1/y-x/3]+3y(x²-y²) 计算（xy-y^2)÷x-y/xy x*-2xy+3y*=9 4x*-5xy+6y*=30