1.-
2x+¿y=¿1
−x+¿2y=¿7
3x+¿y=¿0
}
(
2 1 1
−1 2 7
3 1 0
)
f2−2f1
f3−f1
(
2 1 1
−5 0 5
1 0 −1
)
f2+5f3
(
2 1 1
0 0 0
10−1
)
x = -1 y = 3
2.-
x+¿y+¿z=¿1
2x+¿3y−¿4z=¿9
x−¿y+¿z=¿−1
}
(
1 1 1 1
2 3 −4 9
1−1 1 −1
)
f2−2f1
f3−f1
(
1 1 1 1
0 1 −6 7
0−2 0 −2
)
y = 1 z = -1 x = 1
3.-
{
5x+¿2y=¿2
¿2x+¿3y−¿z=¿3
(
5 2 0
2 1 −1
2 3 −1
|
2
0
3
)
(
1 2/5 0
0 1/5−1
0 11/5−1
|
2/5
0
3
)(
1 2/5 0
0 1 −5
0 11 −5
|
2/5
−4
11
)(
1 2 /5 0
0−10 0
0 11 −5
|
2/5
−15
11
)(
1 2/5 0
0 1 0
0 1 −5/11
|
2/5
3/2
1
)
(
1 0 0
0 1 0
0 0 −5/11
|
−1/5
3/2
−1/2
)
(
1 0 0
0 1 0
0 0 1
|
−1/5
3/2
11/10
)
(
1 0 0
0 1 0
0 0 1
)
= 3
x = -1/5 y = 3/2 z = 11/10
4.-
{
2x−¿y+¿3z=¿5
2x+¿2y+¿3z=¿7
¿
=¿−3¿
(
2−1 3
2 2 3
−2 3 0
|
5
7
−3
)
