-9x^2y-6xy^2+3xy怎么算 这个题

-9x^2y-6xy^2+3xy怎么算 这个题 (9x^2y-6xy^2)/3xy (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， 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 3xy(x^2y-xy^2+xy)-xy^2(2x^2-6xy+2x)过程 x^2-xy-6y^2+3xy+y+2 ①(9x²y-6xy²)÷3xy ②(3x²y-xy²+2分之1xy)÷(-2分之1xy) xy-1+x-y 十字相乘法因式分解怎么做啊xy-1+x-y x2y-3xy-2x+6 3x2+4xy+y2 2x²y-3(2xy-xy)-xy (x^2-xy)y÷y-x/xy怎么做? 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) 已知1/x - 1/y = 2,求3x+7xy-3y / 2x-3xy-2y的值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)=-1/71/x-1/y=2到(y-x)/xy=2 是怎么变化的.. 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) ( )*3xy=6x^2y+2xy^2 [ 2x-6y][8-9xy]÷xy等于? (3xy-9x2-2y2-6xy)-(6x2+2xy-3xy-y) -3x^2y+6xy^2-9xy=( )(x-2y+3)