x^2-2xy+3y^2=9｛4x^2-5xy+6y^2=30

（-3x^y+2xy)-( )=4x^+xy 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) 当x-y=2xy时,求4x-3xy-4y/xy (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， 已知x-y=4xy,求2x+3xy-2y/x-2xy-y的值 x-y=4xy,试求2x+3xy-2y/x-2xy-y 已知x-y=4xy,求x-2xy-y分之2x+3xy-2y的值! x-y=4xy,试求2x+3xy-2y/x-2xy-y 已知X+Y=3,XY=-1,求2(X-Y)^4-9(X-Y)^2+12XY 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 已知x-y=3xy,求5x+2xy-5y/x-4xy-y的值 求（3x^+y^-5xy）-【2x^-（-4xy-y^+7x^）】=? 求（3x^+y^-5xy）-【2x^-（-4xy-y^+7x^）】=? 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] 若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 (-2xy+2x+5y)-(3xy+2y-2x)-(x+4y+xy)其中x-y=4xy=-1 x-y=1,xy=2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值