Answer
a) $y = 10.53*x+88.2$.
b) $m = 10.53$, For every year after 1990, an additional 10.53 million units were sold.
c) y-intercept = 88.2, the number of estimated units sold (in millions) in 1990.
Work Step by Step
The equation of the best fit line was $y = 10.5*x+88.2$. The graph was made in Microsoft Excel.