Over [9, 49], the average rate of change of g(x) is
[tex]\dfrac{g(49) - g(9)}{49 - 9} = \dfrac{14 - 6}{49 - 9} = \dfrac8{40} = \boxed{\dfrac15}[/tex]
Over [25, 81], it would be
[tex]\dfrac{g(81) - g(25)}{81 - 25} = \dfrac{18 - 10}{81 - 25} = \dfrac8{56} = \boxed{\dfrac17}[/tex]
