Question

I am not asking directly for the answer to this problem, I just need help understanding how to work it.
Which of the following rules could be used to describe the function on the table below?
X | Y
-1|-1
0 | 1
1 | 3

a) f(x) = 2x
b) f(x) = 2x - 1
c) f(x) = 2x + 1

Answer 1

f(x) is the same thing as y so if you put y = 2x, and x = -1 that would make y = ?

Answer 2

x 3 4 5 6 7 8 9
y 6 8 9 12 14 16 18