x²-3xy+2y²=0,求(x²+y²)÷(xy)的值?
问题描述：
x²-3xy+2y²=0,求(x²+y²)÷(xy)的值?
答
即(x-y)(x-2y)=0
x=y或x=2y
x=y,则原式=(y²+y²)÷y²=2y²÷y²=2
x=2y,则原式=(4y²+y²)÷2y²=5y²÷2y²=5/2