Okay, it's wrong because they forgot to do -2 times 3x.
The correct answer is

-2x-8
Hope i got is correct!
B.) 81
sq rt of x= 12-3
sq rt of x=9
take the ^2 of both sides to get rid of the sq root
x^2= (9)^2
=81
B I really believe you just got to read it carefully