Answer
The value of the car as a function of x is $V(x)=22,500-3200x,\text{ }0\le x\le 6$, and $V\left( 3 \right)=\$12,900$, which means that the value of the car after 3 years is $\$12,900$.
Work Step by Step
Suppose the value of the car after x years is $V\left( x \right)$, where $0\le x\le 6$. Since the value of the car is decreased by $\$3200$ , the value of the car after x years is given as follows:
$V\left( x \right)=22,500-3200x,\,\,0\le x\le 6$
Put $x=3$ in the above equation to get the value of the car after 3 years:
$\begin{align}
& V\left( 3 \right)=22,500-3200\times 3 \\
& =22,500-9600 \\
& =12,900
\end{align}$
So, the value of the car after 3 years is $\$12,900$.
Thus, the value of the car as a function of x is $V(x)=22,500-3200x,\text{ }0\le x\le 6$ , and the value of car after 3 years is $V\left( 3 \right)=\$12,900$