combining functions

Question

f(x)=x2−4 and g(x)=4x

Step 1 of 2 : Find the formula for (f+g)(x) and simplify your answer.

Then find the domain for (f+g)(x).

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

Domain=???

Answer 1

(f+g)(x) means to add the two functions together:

(f+g)(x) = f(x) + g(x) = x² - 4 + 4x = x² + 4x - 4 [Just rearranged it a bit]

(f+g)(x) is a polynomial, and the domain of polynomials is all real numbers: (-∞,∞).