计算(-1/2x^2y)^3/(-1/3xy^2)^2
计算3xy[2xy-x(y-2)+x-1]
计算(3x^3y-x^2y+1/2xy)÷(-1/2xy)
计算:3xy[2xy-x(y-2)+x]
计算:(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
计算(1)3x/8y×16y²/27x² (2)(2xy-x²)÷x-2y/xy 2x-6
计算:(-7x²y)(2x²y-3xy³+xy)
xy(xy+1)+(xy+3)-2(x+y+2分之一)-(x+y-1)的平方
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
1.计算 (-x方+2xy-y方)-2(xy-3x方)+3(2y方-xy)
计算:(2分之1x^(2)y-2xy+y^(2))·3xy
化简!1、(x^2-xy)+xy+y^2 2、3(x^2-xy)-xy+y^2