a. To find when the cumulative revenue first hit 70 million dollars, we need to solve the equation 0.5t² - 2t + 5 = 70. This is equivalent to solving the quadratic equation 0.5t² - 2t - 65 = 0 for t. This yields two solutions, but since t represents time in years and is used here as a measure of time elapsed since the start of the business, we only keep the positive solution. We'll also convert the decimal part to months by multiplying it by 12.
b. The model predicts that the cumulative revenue for Widgit Company, LLC, at the end of 2020 can be obtained by substituting t = 20 into the equation for r(t), so r(20) = 0.5(20)² - 2(20) + 5.
c. At the end of 2004, the cumulative revenue earned by WidgitCo was 5 million dollars. In function notation, this statement can be written as r(4) = 5, where r is the function that gives the cumulative revenue for any given year t since the start of the business.