Question 34772
if you mean 
3,1,-1,0
1,1,+2,6
2,2,+3,10

divide row 1 by 3/1
1,1/3,-1/3,0
1,1,2,6
2,2,3,10



add  down (-1/1) *row 1 to row 2
1,1/3,-1/3,0
0,2/3,7/3,6
2,2,3,10



add  down (-2/1) *row 1 to row 3
1,1/3,-1/3,0
0,2/3,7/3,6
0,4/3,11/3,10



divide row 2 by 2/3
1,1/3,-1/3,0
0,1,21/6,9
0,4/3,11/3,10



add  down (-4/3) *row 2 to row 3
1,1/3,-1/3,0
0,1,7/2,9
0,0,-1,-2



divide row 3 by -1/1
1,1/3,-1/3,0
0,1,7/2,9
0,0,1,2



add up  (-7/2) *row 3 to row 2
1,1/3,-1/3,0
0,1,0,2
0,0,1,2



add up  (1/3) *row 3 to row 1
1,3/9,0,2/3
0,1,0,2
0,0,1,2



add up  (-1/3) *row 2 to row 1
1,0,0,0
0,1,0,2
0,0,1,2


final
1,0,0,0
0,1,0,2
0,0,1,2


1,0,0,0
0,1,0,2
0,0,1,2

if you mean

3,1,-1,0
1,1,-2,6
2,2,-3,10


divide row 1 by 3/1
1,1/3,-1/3,0
1,1,-2,6
2,2,-3,10



add  down (-1/1) *row 1 to row 2
1,1/3,-1/3,0
0,2/3,-5/3,6
2,2,-3,10



add  down (-2/1) *row 1 to row 3
1,1/3,-1/3,0
0,2/3,-5/3,6
0,4/3,-7/3,10



divide row 2 by 2/3
1,1/3,-1/3,0
0,1,-15/6,9
0,4/3,-7/3,10



add  down (-4/3) *row 2 to row 3
1,1/3,-1/3,0
0,1,-5/2,9
0,0,1,-2



divide row 3 by 1/1
1,1/3,-1/3,0
0,1,-5/2,9
0,0,1,-2



add up  (5/2) *row 3 to row 2
1,1/3,-1/3,0
0,1,0,4
0,0,1,-2



add up  (1/3) *row 3 to row 1
1,3/9,0,-2/3
0,1,0,4
0,0,1,-2



add up  (-1/3) *row 2 to row 1
1,0,0,-2
0,1,0,4
0,0,1,-2


final
1,0,0,-2
0,1,0,4
0,0,1,-2


1,0,0,-2
0,1,0,4
0,0,1,-2