Inverse function f(x)= -5sqrtx-3

Alocal concert promoter purchases 2 3/4 pages of ads. when one of the concerts is cancelled, the promoter cancels 1 5/8 pages of ads. how much advertising space is the concert promoter actually using?

Chanelle deposits $7,500 into the bank. she does not withdraw or deposit money for 6 years. she earns 6% interest during that time. what will the balance be when she is finally able to withdraw her money?

Need solving this second acceleration problem.