Question

If one of the roots of quadratic equation X² – kX + 27 = 0 is 3, then find the value of ‘k’.

Options

• 10

• 12

• –12

• 16

Answer 1

12

Explanation:

Substituting X = 3 in X² – kX + 27 = 0, we get

(3)² – k(3) + 27 = 0

∴ 9 – 3k + 27 = 0

∴ 3k = 36

∴ k = 12