a)
Look for the intersection between the graph of the function and x=5. Then, after 5 years, the copier is worth 6*$1000=$6000. The answer to part a) is $6000
b)
Look for the intersection between the graph and y=12; thus, the answer to part b) is 3 years.
c) The line goes through (0,21000), and (1,18000); thus, the slope of the line is
[tex]\begin{gathered} (0,21000),(1,18000) \\ \Rightarrow m=\frac{21000-18000}{0-1}=-3000 \end{gathered}[/tex]
The slope of the line is -3000.
d) According to the value of the slope of the line, The copier decreased by $3000 in value per year.
e) In general, the equation of the line is given by the formula below,
[tex]\begin{gathered} V=mt+b \\ m\rightarrow slope \\ b\rightarrow y-intersection \end{gathered}[/tex]
From part c), we already know m. As for b, notice that the intersection between the line and the y-axis is (0,21000); therefore,
[tex]\begin{gathered} m=-3000,b=21000 \\ \Rightarrow V=-3000t+21000 \end{gathered}[/tex]
The answer to part e) is V=-3000t+21000
