Metro Department Store's annual sales (in millions of dollars) during the past 5 years were
$$\begin{array}{lccccc}
\hline \text { Annual Sales, } y & 5.8 & 6.2 & 7.2 & 8.4 & 9.0 \\
\hline \text { Year, } x & 1 & 2 & 3 & 4 & 5 \\
\hline
\end{array}$$
a. Plot the annual sales ( $y$ ) versus the year $(x)$
b. Draw a straight line $L$ through the points corresponding to the first and fifth years.
c. Derive an equation of the line $L$
d. Using the equation found in part (c), estimate Metro's annual sales 4 years from now $(x=9)$