Answer:
f(x) = 84 + 6x where x=0, 1, 2, 3, 4, ...
Explanation:
Given 84, 90, 96, 102, 108, ...
the numbers are a sequence with 84 as the initial value and in increment of 6s. So the function can be written as:
f(x) = 84 + 6x where x=0, 1, 2, 3, 4, ...