If you have 313.17 what would it be after tax if the tax is 7.65%

Sara needs to take a taxi to get to the movies the taxi charges $4.00 for the first mile and then $2.75 for each mile after that if the total charge is $20.50 then how far was sara’s taxi ride to the movie

The parabola opens: y=√x-4 (principal square root) up down right left

What are the domain and range of the function f(x)=2^x+1