You should always complete any kind of addition or subtraction before any division/multiplication for these kind of algebra problems. The correct answer for this would be the third option and here's why. While some algebraic problems don't always have a whole number, these types of problems generally do. That is why subtracting the 7 is most important so you are left with a 3x=6. Now this is a simple problem and x= 2. If we divided first it would be x= 11.333. Don't get me wrong, there will be many occasions where you do not get a whole number but in this case you need to get all subtraction/ addition out of the way first.