Assuming the function is linear, it will be f(x) = ax + b
from x=0, f(0)=2, we can see that b must be 2.
then fill in any other point, e.g., x=1:
f(1) = a + 2 = 5, so a = 5-2 = 3
So f(x) = 3x + 2 is the answer.
