Question

If one of the roots of quadratic equation x² – kx – 15 = 0 is – 3, then find the value of ‘k’

Answer 1

– 3 is one of the roots of the equation x² – kx – 15 = 0.

Putting x = – 3 in the given equation, we get

(– 3)² – k(– 3) – 15 = 0

∴ 9 + 3k – 15 = 0

∴ 3k – 6 = 0

∴ 3k = 6

∴ k = `6/3`

∴ k = 2