please help quickly !! can someone reply w an explanation for this? how do I solve problems like these??

Answer:
11:-8x-11
12:6-2y
Step-by-step explanation:
If you have to simplify then do this
#11:
-9x-5-6+x
combine like terms
-8x-11
#12:
6-y+5y-6y
6-7y+5y
6-2y