Question

If f(x) = x2 – 2x and g(x) = 6x + 4, for which value of x does (f + g)(x) = 0?

-4
-2
2
4

Answer 1

x = - 2

Explanation:

(f + g)(x) = f(x) + g(x)

f(x) + g(x)

= x² - 2x + 6x + 4

= x² + 4x + 4

Equating to zero

x² + 4x + 4 = 0 ← left side is a perfect square

(x + 2)² = 0, thus

x + 2 = 0 ( subtract 2 from both sides )

x = - 2