Start by substituting the appropriate numbers in for
your variables, using parenthses as you go.
You'll get 4(12) - (8)(3).
Now think about your order of operations.
Multiplication comes before subtraction.
So first multiply 4(12) to get 48.
So we have 48 - (8)(3).
Now multiply (8)(3) to get 24.
So we have 48 - 24 which is 24.