I have the answers already, but I need help with the step-by-step on how to get the answers.

The accompanying data represent the yearly amount of solar power installed (in megawatts) in a particular area from 2000 through 2008. The trend forecasting equations below were found, where X is the number of years after 2000.

Data set is

Year	Amount
2000	15
2001	22
2002	41
2003	72
2004	88
2005	97
2006	144
2007	206
2008	248

Question a and b: