Respuesta :
[tex]\bf slope = \cfrac{rise}{run} \implies
\cfrac{{{ y_2}}-{{ y_1}}}{{{ x_2}}-{{ x_1}}}\implies \cfrac{f(x_2)-f(x_1)}{x_2-x_1}\leftarrow
\begin{array}{llll}
\textit{average rate}\\
\textit{of change}
\end{array}\\\\
-----------------------------\\\\
f(x)=x^2+3x+5\qquad
\begin{cases}
x_1=1\\
x_2=3
\end{cases}\implies \cfrac{f(3)-f(1)}{3-1}[/tex]
that's just the slope between the 2 points
evalue f(1) and f(3)
f(1)=1+3+5=9
f(3)=9+9+5=23
slope between (1,9) and (3,23) is
(23-9)/(3-1)=14/2=7
average rate of change is 7
evalue f(1) and f(3)
f(1)=1+3+5=9
f(3)=9+9+5=23
slope between (1,9) and (3,23) is
(23-9)/(3-1)=14/2=7
average rate of change is 7