(-2x)×(-xy²)×3y=?

已知x:y=3:2,求(x²+3xy)/(xy+2xy) 已知x/y=3,求(x²+2xy-3xy²)/(x²-xy+y²) 已知：X+Y=-3,XY=2,X²Y+XY² 化简求值3x²y-[2xy-2（xy-3/2x²y)+xy]+3xy²其中x=3、y=-1 3xy²-[xy-2(xy-3/2x²y)+3xy²]+3xy²,其中x=3,y 已知x+y=4.x-y=6.求代数式xy(y²+y)-y²(xy+2x)-3xy的值 （-3x^y+2xy)-( )=4x^+xy 若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy( 已知X/Y=2,则X²+2XY-3Y²/X²-XY+Y²=? 已知x/y=3,求x²+2xy-3y²/x²-xy+y² 已知y分之x=3,求x²-xy+y²分之x²+2xy-3y² 已知x/y=3,求x²+2xy-3y²/x²-xy+y²的值