Answer:
f(x) = 2x +1
Step-by-step explanation:
Apparently the ordered pairs are ...
(x, f(x)) = (1, 3), (2, 5), (3, 7), (4, 9)
We note that as x increases by 1, the value of f(x) increases by 2. The difference between f(x) and 2x is 3-2·1 = 1, so we have ...
f(x) -2x = 1
f(x) = 2x +1 . . . . . . add 2x
