Question 1140945


Your matrix

{{{matrix(3,4,
-3,	1,	-1,	4,
2,	-1,	1,	-8,
4,	-3,	2,	12)}}}


Make the pivot in the 1st column by dividing the 1st row by {{{-3}}}:


{{{matrix(3,4,
1,	-1/3,	1/3,	-4/3,
2,	-1,	1,	-8,
4,	-3,	2,	12)}}}


Eliminate the 1st column:


{{{matrix(3,4,

1,	-1/3,	1/3,	-4/3,
0,	-1/3,	1/3,	-16/3,
0,	-5/3,	2/3,	52/3)}}}



Make the pivot in the 2nd column by dividing the 2nd row by {{{-1/3}}}:



{{{matrix(3,4,
1,	-1/3,	1/3,	-4/3,
0,	1,	-1,	16,
0,	-5/3,	2/3,	52/3)}}}



Eliminate the 2nd column:


{{{matrix(3,4,

1,	0,	0,	4,
0,	1,	-1,	16,
0,	0,	-1,	44)}}}

Find the pivot in the 3rd column in the 3rd row (inversing the sign in the whole row)


{{{matrix(3,4,
1,	0,	0,	4,
0,	1,	-1,	16,
0,	0,	1,	-44)}}}


Eliminate the 3rd column:


{{{matrix(3,4,

1,	0,	0,	4,
0,	1,	0,	-28,
0,	0,	1,	-44)}}}


Solution set:

{{{x[1] = 4}}}
{{{x[2] = -28}}}
{{{x[3] = -44}}}