Use the rise over run formula to find the rate of change of the table:
y2 - y1 / x2 - x1
Take any two ordered pairs and plug in the values into the formula. We'll take (1,2) and (3,10).
[tex] \frac{10-2}{3-1} = \frac{8}{2} = 4[/tex]
The constant rate of change for this table is 4.