已知xy不等於0,且2x^2+5xy-3y^2=0,則x^2-y^2/xy的值是?

題目：

已知xy不等於0,且2x^2+5xy-3y^2=0,則x^2-y^2/xy的值是?

解答：

2x^2+5xy-3y^2=0
(2x - y)(x + 3y) = 0
y = 2x 或者x = -3y
當y = 2x時
(x^2-y^2)/xy = x/y - y/x = 1/2 - 2 = -3/2
當x = -3y時
(x^2-y^2)/xy = x/y - y/x = -3 + 1/3 = -8/3