(-2xy^2)*(3x^2y)^2 怎么算

2x²y-3(2xy-xy)-xy 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 x^2-xy-6y^2+3xy+y+2 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) X^Y-2XY^2+y^3 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] xy-2{xy-[3x^2y-(4xy^2+0.5xy)]+4x^2y}+6xy^2 （X-3xy+4xy-y）-[-2x-2（xy-3/2xy）-y]+6xy的过程 计算：3xy[2xy-x（y-2）+x] 计算3xy[2xy-x(y-2)+x-1] （-3x^y+2xy)-( )=4x^+xy x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? x^2-xy/xy-y^2约分 (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， （x^2+xy/x-y)/（xy/x-y)计算 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 3xy(x^2y-xy^2+xy)-xy^2(2x^2-6xy+2x)过程 (-1/3xy)^2•[xy(2x-y)-2x(xy-y^2)]