If kx^2 + 3xy – 2y^2 = 0 represent a pair of lines which are perpendicular then k is equal to: (a) 1/2 (b) -1/2 (c) 2

Question

If kx² + 3xy – 2y² = 0 represent a pair of lines which are perpendicular then k is equal to: 

(a) \(\frac{1}{2}\)

(b) -\(\frac{1}{2}\)

(c) 2

(d) -2

Answer 1

(c) 2

Here a = k, b = -2 

Condition for perpendicular is 

a + b = 0

⇒ k – 2 = 0 

⇒ k = 2