Answer:
f(a + 1) = 3a + 4
Explanation:
Given the function is:
f(x) = 3x + 1
To determine f(a + 1) we have to substitute (a + 1) in place of 'x'.
Therefore, we have:
f(a + 1) = 3(a + 1) + 1
= 3a + 3 + 1
= 3a + 4
['a' could be any real number.]
So, f(a + 1) = 3a + 4 is the answer.