Please help I am so lost

4. Interpreting a Cubic Function The following function, P(t) = (t - 2.6) (t - 4.5)2 models the annual profit in $ millions of a mid- size marketing firm with t in years from start-up in 2012 (t = 0 is the year 2012). Without graphing the function on DESMOS, answer the following questions: a) Is the profit increasing or decreasing after 2017? Justify your answer by finding the end- behaviour. b) For what values of z is the profit zero? (1-intercepts) c) Roughly sketch the function and state the interval for t in which the profit is negative in the practical domain