已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以（x2+y2/xy）2乘1/x+y的值
问题描述：
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以（x2+y2/xy）2乘1/x+y的值
答
(x⁴ - y⁴) / (2x-y) × (2xy - y²) / (xy -y²) ÷ [ (x²+y²) / (xy) ]² × 1/(x+y)= (x²+y²)(x+y)(x-y) / (2x-y) × y(2x-y) / [ y(x-y)] × x²y² / (x...