Question

If f(x) = 2x² and g(x) = 5x + 2, what is (f + g)(x) when x = 3?

Answer 1

(f + g)(3) = 35

Explanation:

The expression (f + g)(x) is equal to f(x) + g(x). In other words, you want to add both expressions.

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

(f + g)(x) = (2x²) + (5x + 2) <----- Insert function

(f + g)(x) = 2x² + 5x + 2 <----- Combine function

Now that we have the (f + g)(x) function, we can insert x = 3 and solve for the answer.

(f + g)(x) = 2x² + 5x + 2 <----- Function

(f + g)(3) = 2(3)² + 5(3) + 2 <----- Plug 3 into "x"

(f + g)(3) = 2(9) + 15 + 2 <----- Solve (3)² and 5(3)

(f + g)(3) = 18 + 15 + 2 <----- Solve 2(9)

(f + g)(3) = 35 <----- Add