# How do you find the average rate of change of f(x)=x^2 + x over [1,3]?

Oct 15, 2015

5

#### Explanation:

$f \left(1\right) = {1}^{2} + 1 = 2$

$f \left(3\right) = {3}^{2} + 3 = 12$

Average rate of change= $\frac{f \left(3\right) - f \left(1\right)}{3 - 1} = \frac{10}{2} = 5$