(-6)-9 is the same as -6-9 since parenthesis aren’t really needed in thins case and if you use the order of operations you go left to right. So, -6-9=-15 because a negative- a negative= a negative.
7,500 plus the commision is 525 now you add it to the 7,500 that will leave you with 8,025 now you subtract it from 185,000 so the answer will be 176,975