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.

Answer 1

Order of Operations:

To simplify the expression follow the order of operations: (PEMDAS)

1.      Evaluate the expressions inside the Parenthesis/Brackets (P).

2.      Evaluate Powers/Exponents (E).

3.      Multiply and/or Divide in order from left to right (MD).

4.      Add and/or Subtract in order from left to right (AS).

A simple technique for remembering the order of operations is turned into phrase "Please Excuse My Dear Aunty Sally"

First operation is evaluating powers.

Evaluate powers: 12^2 = 12 × 12 = 144 and 4^2 =  4 × 4 = 16.

 = 144 + 9 - 16

Next operation is addition.

Add: 144 + 9 = 153.

= 153 - 16

Next operation is subtraction.

Subtract: 153 - 16 = 137

= 137