(xy-x^2)-(x2-2xy+y^2)/xy×(x^2-y^2)/x^2 -xy-y^2

(xy-x^2)-(x2-2xy+y^2)/xy×(x^2-y^2)/x^2 -xy-y^2 4x2-y2/x2-2xy+y2 +(2x-y)/2x2-2xy (3xy-9x2-2y2-6xy)-(6x2+2xy-3xy-y) 若2x+y=0则(x2+xy+y2)/(2xy-x2)的值 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） 若x-y/x+y=2,则x2+2xy+y2/4xy=多少 25(x2+ 2xy +y2)-9(x2-2xy+y2)因式分解.x2,y2是x平方,y平方的意思.2xy就是2xy.快, 2(x-xy)-3(2x2-3xy）2[x2（2x2-xy+y2)] -(x2²-2xy-y²)+(5x²-2xy-3y²)化简 [2/xy/(1/x+1/y)2+(x2+y2)/(x2+2xy+y2)]*2x/(x-y) x^2-xy/xy-y^2约分 x2-2xy-3y2=0,其中x,y均不为零,求（y-x）/x2-xy/2x-y-y2/xy-x 因式分解x2-4xy+4y2+x-2y-2 x2-4xy+4y2-x+2y-2因式分解 x2+2xy-3y2+3x+y+2 因式分解 因式分解x2+2+y2-3x-2xy+3y x2+2xy-8y2+2x+8y因式分解 (x2+y2)2与xy(x+y)2的大小