Chapter 12.3, Problem 34E

Work these exercises.

Consumer Spending Average consumer expenditures on all items (in dollars) during the years 2004 through 2014 can be approximated by

$S\left(x\right)=38x^2-106x^2+9728x+20,680,$

where $x=4$ corresponds to the year 2004. Find and interpret the absolute extrema of $S\left(x\right)$ for $4\le x\le 14$ (Data from: ProQuest Statistical Abstract of the U.S.: 2016.)