Answer:
[tex]\boxed{\text{x = -2}}[/tex]
Step-by-step explanation:
ƒ(x) = x² - 2x
g(x) = 6x + 4
(f + g)(x) = x² - 2x + 6x + 4 = x² + 4x + 4
[tex]\begin{array}{rcr}x^{2} + 4x + 4 & = & 0\\(x + 2)^{2} & = & 0\\x+2 & = & 0\\x & = & \mathbf{-2}\\\end{array}[/tex]
[tex](f + g)(x) = 0 \text{ when } \boxed{\textbf{x = -2}}[/tex]
Check:
[tex]\begin{array}{rcl}(-2)^{2} + 4(-2) + 4 & = & 0\\4 - 8 + 4 & = & 0\\0 & = & 0\\\end{array}[/tex]
OK.
