To determine the initial length, we have to evaluate the given equation at x=0. Evaluating the equation, we get:
[tex]y=3\cdot0+59.[/tex]
Therefore, the initial length of the road was 59 miles.
Now, notice that the given equation is a linear equation in slope-intercept form y=mx+b, where b is the slope, recall that the slope of a line represents the change of y compared to the change in x, in this case, miles per day.
Therefore, the change per day in the road's length is 3 miles.
Answer:
a) 59 miles.
b) 3 miles.
