A franchise owner operates two coffee shops. The sales, Sı, in thousands of dollars for Shop One is represented by S1(t) = 700 – 1.4t², where t = 0 and corresponds to the year 2020. Similarly, the sales for Shop Two is represented by s2(t) = t³+ 3t² + 500.
a) Which shop is showing an increase in sales after the year 2020? Explain how you know.