Respuesta :

The answer is 21 because 9+10=21 see im smart
first you multiply 3 times everything in the parenthesis, then we end up with (3t+15t-18+27)-15t then we add 3t+15t=18t        -18+27=11 so we end up with something like this (18t+11)-15t      18t+11=29t      29t-15t=14t