The first way is to algebraically find (f+g)(x) first and plug in x = 5 later. Doing that method leads us to (f+g)(x) = f(x) + g(x) (f+g)(x) = 6x+3 + x-4 (f+g)(x) = 7x-1 (f+g)(5) = 7(5)-1 (f+g)(5) = 34
OR
you can compute f(5) and g(5) first, then add up those sub-results to get f(x) = 6x+3 f(5) = 6(5)+3 f(5) = 33 g(x) = x-4 g(5) = 5-4 g(5) = 1 Adding up these results gives: (f+g)(5) = f(5) + g(5) = 33+1 = 34
