Qasim, First check your brake fluid If it is okay I have a feeling your brake booster is the issue.
The ac depends on which car you drive. because if you drive a wrangler and expect nissan sunny cooling it is never gona happen.
Brake problem could be any number of things. Low pads, old fluid, air in the fluid. You need a mechanic to look at it.
AC problem could be a weak compressor, dirty condenser, maybe the system wasn't cleaned and vacuumed properly before being filled, again any number of things. You need to see a good mechanic.