Explanation:
the average rate of change between two input values is the total change of the function values (output values) divided by the change in the input values.
so,
(g(4) - g(-5)) / (4 - -5)
g(4) = 4² + 5×4 + 1 = 37
g(-5) = (-5)² + 5×-5 + 1 = 25 - 25 + 1 = 1
4 - -5 = 4 + 5 = 9
(37 - 1)/9 = 36/9 = 4
the average change rate in that interval is 4 (or fully 4/1).