Erry started doing sit-ups every day. the first day he did 11 sit-ups. every day after that he did 2 more sit-ups than he had done the previous day. today jerry did 25 sit-ups. write an equation that could be solved to find the number of days jerry has been doing sit-ups, not counting the first day. let n represent the number of days. an equation that can jerry to find the number of days he has been doing sit-ups is given by