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

A.-4

B.-2

C. 2

D. 4

B

Step-by-step explanation:

note that (f + g) (x) = f (x) + g (x), thus

f (x) + g (x) = x² - 2x + 6x + 4 = x² + 4x + 4

Equating to zero gives

x² + 4x + 4 = 0 ← in standard form

(x + 2) ² = 0 ← in factored form, thus

x + 2 = 0 ⇒ x = - 2 → B