1. The problem statement, all variables and given/known data Here is the problem: http://img801.imageshack.us/img801/6770/oaza.png [Broken] 2. Relevant equations None really, just gauss jordon elimination I assume unless I am missing out on something 3. The attempt at a solution First I multiplied the first row by -5 then added it to the second row to obtain the following: 1 1 5 3 0 -1 -27 -8 and then multiplied the second row by 1 and added the result to the first row to obtain: 1 0 -22 -5 0 -1 -27 -8 I then tried to solve inputting the numbers into the boxes but apparently I can't put letters or x1 x2 x3 etc.. meaning that the solution is just numbers ie: 1 + 2 is the solution, which is not what I got. My question is, and im having a little trouble wondering what they want is why do they have 2 separate columns? Am I supposed to transpose afterwards or did I make a mistake doing the elimination progress, I more or less want to know the steps more than anything as I have more questions like this one and have no idea how to go about them. here are the other 2 : http://img694.imageshack.us/img694/5315/m0a5.png [Broken] http://img843.imageshack.us/img843/4208/2cu0.png [Broken] thanks in advance!