Evaluating $-3(5-7)^2$: multiply by $-3$ or square it first?

Question

As stupid as this is, I don't know.
$$-3(5-7)^2$$
Multiply by $-3$ or square it first?

Answer 1

Hint: Use the mnenomic PEMDAS (Please Excuse My Dear Aunt Sally) for order of operations: Parentheses, Exponents, Multiplication, Division, Addition, and Subtraction.

In your case, take care of items inside the parenthesis first ($5-7 = -2$), then square ($-2^2 = 4$) and finally multiply ($-3 \cdot 4 = -12$).