Question 887568
{{{(matrix(3,4,
1,-9,-1,-17,
1,-1,1,7,
1,1,-1,3
))}}}


R2=R2-R1, R3=R3-R1


{{{(matrix(3,4,
1,-9,-1,-17,
0,8,2,24,
0,10,0,20
))}}}


R2=(1/8)R2, R3=(1/10)R3


{{{(matrix(3,4,
1,-9,-1,-17,
0,1,1/4,3,
0,1,0,2
))}}}


Notice that already we have y=2.


Switch R2 and R3


{{{(matrix(3,4,
1,-9,-1,-17,
0,1,0,2,
0,1,1/4,3
))}}}


R3=R3-R2


{{{(matrix(3,4,
1,-9,-1,-17,
0,1,0,2,
0,0,1/4,2
))}}}

Multiply R3 by 4.


{{{(matrix(3,4,
1,-9,-1,-17,
0,1,0,2,
0,0,1,8
))}}}


R1=R3+R1
and then
R1=9*R2+R1


{{{(matrix(3,4,
1,-9,0,-25,
0,1,0,2,
0,0,1,8
))}}}
---
{{{highlight((matrix(3,4,
1,0,0,-7,
0,1,0,2,
0,0,1,8
)))}}}


x=-7
y=2
z=8