Which expression can be used to check the answer to 56+(-14)=n?

Asales representative from a local radio station is trying to convince the owner of a small fitness club to advertise on her station. the representative says that if the owner begins advertising on the station today, the club's total number of members will grow exponentially each month. she uses the given expression to model the number of club members, in hundreds, after advertising for t months.

Can someone me and explain..will award brainlest!

Add. express your answer in simplest form. 12 9/10+2 2/3 = i need u guys to me find the answer to this question