(2xy/x2-y2)+(x+y/x)-(y/y-x)计算

(x-y)(x2+xy+y2) (x+y)(x2-xy+y2) 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） 4x2-y2/x2-2xy+y2 +(2x-y)/2x2-2xy x2-2xy+y2=4 x2+y2-x-y=6 解不等式x2-2xy+y2=4 x2+y2-x-y=6 解不等式 因式分解x2+y2-xy-x-y+1 x2-4y2-3xy+y+x (x-y)(x2+xy+y2)-xy(y-x) [2/xy/(1/x+1/y)2+(x2+y2)/(x2+2xy+y2)]*2x/(x-y) 已知x2+4y2+x2y2+1=6xy,则(x4-y4)/(2x2+xy-y2)*(2x-y)/(xy-y2)/(x2+y2/y)2= 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 x2-xy-2y2-x+5y-2 (-x-2y)(x2-2xy+4y2)等于多少