Question

S = 0.4t^3 - 4.5t^2+ 9.2t + 202 During which year did sales reach a low point

Answer 1

S' = 1.2t² - 9t + 9.2 = 0

6t² - 45t + 46 = 0

t = (45 ± √((-45)² - 4(6)(46)))/(2(6))

= (45 ± √921)/12

= about 1.221, 6.279

Sales reached a low point in year 6.