Question

If x = 3 is a root of the quadratic equation x² + mx – 9 = 0 then find the value of m.

Answer 1

Given:

x² + mx − 9 = 0

Substitute x = 3:

(3)² + m(3) − 9 = 0

9 + 3m − 9 = 0

3m = 0

m = 0