Answer
See the table below.
Work Step by Step
$ \left[\begin{array}{llllll}
& & & f(x)=x^2+2x & & \frac{f(a+h)-f(h)}{h}\\
& & & & & Avg.rate.\\
\mathrm{a} & h & a+h & f(a+h) & f(a) & of.change\\
& & & & & \\
3 & 1 & 4 & 24 & 15 & 9\\
3 & 0.1 & 3.1 & 15.81 & 15 & 8.1\\
3 & 0.01 & 3.01 & 15.0801 & 15 & 8.01\\
3 & 0.001 & 3.001 & 15.008001 & 15 & 8.001\\
3 & 0.0001 & 3.0001 & 15.00080001 & 15 & 8.0001
\end{array}\right]$
