Question

If one zero of the quadratic polynomial x² + 3x + k is 2, then the value of k is ______.

Options

• 10

• - 10

• 5 

• - 5

Answer 1

If one zero of the quadratic polynomial x² + 3x + k is 2, then the value of k is - 10.

Explanation:

Let f(x) = x² + 3x + k

f(2) = (2)² + 3(2) + k = 0

4 + 6 + k = 0

k = - 10