Question

Which of the following equation does not represent a pair of lines?

पर्याय

• x² + y² + 2xy - 1 = 0

• x² - y² - x = 0

• x² - y² - 2y - 1 = 0

• 15xy + 10x + 6y + 4 = 0

Answer 1

x² - y² - x = 0

Explanation:

Consider option (x² - y² - x = 0),

Given equation is x² - y² - x = 0

∴ a = 0, b = -1, c = 0, f = 0, g = `(-1)/2, h = 0`

Now, abc + 2fgh - af² - bg² - ch²

= 0 + 0 - 0 - `(1/4) - 0 = (-1)/4 ≠ 0`

∴ The equation does not represent a pair of straight Lines.