How do I solve this? What's the formula I can use?

What is the inverse of the function f(x) = 2x + 1?

Raymond just got done jumping at super bounce trampoline center. the total cost of his session was $43.25 . he had to pay a $7 entrance fee and $1.25 for every minute he was on the trampoline. write an equation to determine the number of minutes (t) that raymond was on the trampoline.

Write the equations in logarithmic form 9^4=6,561