x>y>o xy=2 求证 (x2+y2)除以x-y大于等于4

已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以（x2+y2/x 您好 X2-y2=2xy,求x-y除以x+y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xy大于0求证xy+1/xy+y/x+x/y大于等于4 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 实数X,Y满足X大于等于Y大于等于1和2X平方-xy-5x+y+4=o,则x+y的值 已知x＞y,且xy=1,求证：(x2+y2/x-y)≥2根号2 已知2x=3y,求xy／(x2+y2)-y2／(x2-y2)的值 X2+Y2+8X+6Y+25=0 求代数式(x2-4y2/x2+4xy+4y2)-x/x+2y 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 2x2+xy-3y2+x+4y-1因式分解 正整数x,y满足x2-y2=2xy,求x-y/x+y的值