3x^2-xy/9x^2-6xy+y^2,其中x=-8,y=2.

(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， (9x^2y-6xy^2)/3xy 3xy(x^2y-xy^2+xy)-xy^2(2x^2-6xy+2x)过程 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 x^2-xy-6y^2+3xy+y+2 2x²y-3(2xy-xy)-xy 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) ①(9x²y-6xy²)÷3xy ②(3x²y-xy²+2分之1xy)÷(-2分之1xy) ( )*3xy=6x^2y+2xy^2 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 [ 2x-6y][8-9xy]÷xy等于? -3x^2y+6xy^2-9xy=( )(x-2y+3) 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 计算：3xy(x²y-xy²+xy)-xy²(2x-xy+2x） 计算：3xy[2xy-x（y-2）+x] 计算3xy[2xy-x(y-2)+x-1]