Question

Gaussian Elimination Method, help!

Answer 1

Here is my augmented matrix

[
3 -1 1 -5 -1 0
6 -2 2 -9 1 0
-9 3 -3 11 -1 0
]

Answer 2

I first tried to add the second row with (-2)R1

Answer 3

@johnweldon1993 @mathstudent55 @ganeshie8

Answer 4

@triciaal

Answer 5

and then I added -3R1 to row 3

but I get

[ 3 -1 1 -5 -1 0
0 0 0 1 1 0
0 0 0 -12 -12 0 ]

Answer 6

is that okay? can I assign parameters to x4 and x5?

Answer 7

As I mention in your other question, you have some computational errors in the fifth column of your reduced matrix.
http://openstudy.com/study#/updates/57c5fddee4b0d57cf6c517c4