Hello! Since f(a) = 5a + 12, you need to substitute the a values into the equation.
For example, 1:
1. a = 6; you will substitute the a value for 6.
f(a) = 5a + 12
f(a) = 5(6) + 12
f(a) = 30 + 12
f(a) = 42
Do the same for the other ones. This will help you not fail math.