im going to assume that you need the two numbers subtracted from each other,, but if it happens to be something else let me know and i will help you find the correct answer.
the first step to solving this is to replace the b in the expression with 1. this will look like the following:
33(1)-40
any expression multiplied by 1 remains the same so the expression becomes
33 - 40
calculate the difference
-7
the correct answer to your question is -7.
let me know if you have any further questions
:)