Answer:
-8
Step-by-step explanation:
GIven a function [tex]f(x)[/tex], the rate of change of the function over an interval [tex]x_1,x_2[/tex] is given by
[tex]r=\frac{f(x_2)-f(x_1)}{x_2-x_1}[/tex]
where
[tex]f(x_2)[/tex] is the value of the function calculated in [tex]x_2[/tex]
[tex]f(x_1)[/tex] is the value of the function calculated in [tex]x_1[/tex]
In this problem, the function is
[tex]f(x)=-x^2-4x+2[/tex]
The interval is
[tex]x_1=1\\x_2=3[/tex]
So we have:
[tex]f(x_1)=f(1)=-(1)^2-4(1)+2=-3[/tex]
[tex]f(x_2)=f(3)=-(3)^2-4(3)+2=-19[/tex]
Therefore, the rate of change of the function is
[tex]r=\frac{-19-(-3)}{3-1}=\frac{-16}{2}=-8[/tex]