The function f (x) represents the time it takes a boat to travel upstream. The function g (x) represents the time it takes a boat to travel downstream. Given f (x) = 3x - 10 and g (x) = 12x + 8, solve for (f + g) (x) to determine the total roundtrip time.

(f + g) (x) = 15x - 2

(f + g) (x) = 9x - 2

(f + g) (x) = 15x + 2

(f + g) (x) = 9x + 2

(f + g) (x) = 15x - 2

Step-by-step explanation:

The function f (x) represents the time it takes a boat to travel upstream. The function g (x) represents the time it takes a boat to travel downstream.

Now, given that f (x) = 3x - 10 and g (x) = 12x + 8, and we have to determine (f + g) (x) for the total round trip time.

So, (f + g) (x) = f (x) + g (x) = (3x - 10) + (12x + 8) = 15x - 2

Hence, (f + g) (x) = 15x - 2 (Answer)