An internet service provider charges $18 per month plus initial set up fee. Once customer paid a total of $81 after 2 months of service. What is the initial set up fee and how much does it cost after 5 months of service

18*m + fee = charge

at 2 months the charge is 81 so substitute in

18*2 + fee = 81

36+fee=81

subtract 36 from both sides

fee = 45

for 5 months what is the charge

18*m + fee = charge

18*5 + 45 = charge

90 + 45 = charge

135

Answer: the initial fee is $45 and the 5 month fee is $135

364.5 i am pretty sure not 100% sure but i belive it is