Consider x as the length of the pieces before the cut of the three inches.
After the cut of three inches, each piece will have a length of x-3.
The total length of the five pieces is five time the expression x-3:
Hence, the expression for the total length of the five pieces can be written as follow:
f(x) = 5(x - 3)
where f(x) is the function which determines the total length