xy分之x2-y2除以（x+y)

已知2+4y2-4x+4y+5=0,求x四次方-y的四次方/xy乘以2x2-xy/xy-y2除以(y分之x2+y2)2 已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以（x2+y2/x 正数xy满足x2-y2=2xy,求x+y分之x-y的值 您好 X2-y2=2xy,求x-y除以x+y的值. 已知X2+Y2+8X+6Y+25=0 求代数式X2++XY+4Y2分之X2-4Y2 减X+2Y分之X的值 已知2x-3*根号(xy)-2y=0(x>0),则x2+4xy-16y2除以2x2+xy-9y2的值是多少? 已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值 已知2x=3y,求xy／(x2+y2)-y2／(x2-y2)的值 x2-xy-2y2-x+5y-2 因式分解 x2+xy-2y2-x+7y-6 x2-2xy+y2+3x-3y+2． 2x2+xy-3y2+x+4y-1因式分解