Final answer:
To find (f + g)(x), combine like terms within f(x) first to get f(x) = 13x, then add g(x) = 5x - 3 to this result. The sum (f + g)(x) is 18x - 3, which is option A.
Step-by-step explanation:
The student is asking to find the sum of the functions f(x) and g(x). This operation is denoted as (f + g)(x). To find this, you align the functions and add the corresponding terms:
f(x) = 3x + 10x
g(x) = 5x - 3
Combine the like terms in f(x):
f(x) = (3x + 10x) = 13x
Now add the corresponding terms from f(x) and g(x):
(f + g)(x) = (13x) + (5x - 3) = 13x + 5x - 3 = 18x - 3
The correct answer is A. 18x - 3.