I'm attempting to help my son with algebra I need to see the math to assist 12^2+9-4^2

Question

The equation started as a^2+b-c^2

The instructions say "Evaluate each expression if a = 12, b = 9, and c = 4.

So I took that as a simplify of 12^2+9-4^2

144+9-8 <~ This is the step I think I'm messing up at. According to the law of operations I am to do multiplication before addition and subtraction. Does that still apply to powers? Do I work powers before I do the addition and/or subtraction? I'm attempting to find my error in thought.

I know the answer should be 137, however my way of math comes up with 145. I can not figure out how they came up with 137 with the problem provided. Please help!

Mom in Texas attempting to assist my Freshman after 25 years out of Algebra and NO TEXT BOOK.

Answer 1

12^2 +9 -4^2=144+9 -16

=137

Answer 2

http://www.mathskey.com/question2answer/4469/attempting-help-son-with-algebra-need-see-the-math-assist-12