Question 869344
3,-5,3
15,5,21

divide row 1 by 3
1,-5/3,1
15,5,21

add  down (-15) *row 1 to row 2
1,-5/3,1
0,30,6

divide row 2 by 30
1,-5/3,1
0,1,6/30

add  (5/3) *row 2 to row 1
1,0,20/15
0,1,1/5


1,0,4/3 
0,1,1/5