1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution Do you see how 1 1 1 changes to 3 3 3. i know why gaussian elimination you can change any vector by multiplying it by anything you want. but for some reason i have difficulty believing that you're allowed to do that here. is that what they're doing? just multiplying that vector by 3 so as to facilitate the arithmetic. Or maybe they're multiplying both vectors by 3, so as to get rid of the 1/3, but that doesn't explain how the 1/3 gets on the left side of the parentheses.