Question

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

Answer 1

Answer:

x = - 2

Step-by-step explanation:

Answer 2

Answer:

x = - 2

Step-by-step explanation:

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

x² + 4x + 4 = 0 ← This is a perfect square in the form

(x + a)² = x² + 2ax + a²

Hence 2a = 4 ⇒ a = 2, thus

(x + 2)² = 0

x+ 2 = 0 ⇒ x = - 2 ( 2 equal roots )

Value of x = - 2