Answer
$\dfrac{15}{8}$
Work Step by Step
Average rate of change is: $ \dfrac{f(x_2)-f(x_1)}{x_2-x_1}$
So, $ \dfrac{f(x_2)-f(x_1)}{x_2-x_1}= \dfrac{[-(1.125)^2+(4)(1.125)-3]-[-(1)^2+(4)(1)-3]}{1.125-1}$
or, $=\dfrac{\dfrac{15}{64}-0}{0.125}$
or, $=\dfrac{15}{8}$