The slope of the secant line is the same thing as the average rate of change.
The average rate of change from an interval from [tex]x_1[/tex] to [tex]x_2[/tex] is the change in the value of the function divided by the change in x.
[tex]\dfrac{f(x_2)-f(x_1)}{x_2-x_1}[/tex]
Let's find the values of [tex]f(x_1)[/tex] and [tex]f(x_2)[/tex]
[tex]f(x_1)=570[/tex]
[tex]f(x_2)=1198.8[/tex]
[tex]\dfrac{f(x_2)-f(x_1)}{x_2-x_1}[/tex]
[tex]= \dfrac{1198.8-570}{4-0}=157.2 \approx 157[/tex]
Your answer rounded to the nearest whole number is 157.
