2xy-{5x-3[xy-1/3x(y+1)]-4xy} 去掉括号,并合并.

5x^2y/-1/2xy*3xy^2 5xy^2-{2x^y-[3xy^2-（xy^2-2x^2y）]/（-1/2xy）} 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= 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] 【x(xy-xy)-y(x-xy)】÷3xy 若x-y=4,xy=1,则(2x+y-2xy)-(3x+2y+xy)-(4xy+3y-5x)= (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 计算：(5-xy/x^3-x^2y)/(1-5/xy)^2*(y-x)^3 2x²y-3(2xy-xy)-xy 化简(3x^2-5xy)+{-x^2-[-3xy+2(x^2-xy)+y^2]} 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) xy(xy+1)+xy+3-2(x+y+1/2)-(x+y-1)^2因式分解 (-1/3xy)^2•[xy(2x-y)-2x(xy-y^2)] (-3分之1xy)的平方×[xy(2x-y)-2x(xy-y的平方)] XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2)