Hello,
when x = 0 f(x) is -5 as (0,-5) is on the graph
each time x increases by 1 f(x) increases by
as (3,4) and (0,-5) are on the graph
[tex]\dfrac{4-(-5)}{3-0}=\dfrac{4+5}{3}=\dfrac{9}{3}=3[/tex]
Finally
f(x) = 3x - 5
hope this helps
