Me need help on this fast help

Given f(x)= 9x+1 and g(x)=x^3, choose the expression (f*g)(x)

Ian is in training for a national hot dog eating contest on the 4th of july. on his first day of training, he eats 4 hot dogs. each day, he plans to eat 110% of the number of hot dogs he ate the previous day. write an explicit formula that could be used to find the number of hot dogs ian will eat on any particular day.

Find the percent error of the measurement 4 cm