Yaitu sistem persamaan linear (SPL) yang semua suku konstan atau nilai ruas kanannya adalah nol.
Bentuk umum:
- a11x1 + a12x2 + ... + a1nxn = 0
- a21x1 + a22x2 + ... + a2nxn = 0
- am1x1 + am2x2 + ... + amnxn = 0
Sistem Persamaan Linear Homogen 3 Persamaan dan 3 Variabel
- a11x1 + a12x2 + a13x3 = 0
- a21x1 + a22x2 + a23x3 = 0
- a31x1 + a32x2 + a33x3 = 0
SPL Homogen dapat diselesaikan dengan metode Operasi Baris Elementer. Maka, SPL Homogen tersebut diubah menjadi matriks:
![{\displaystyle \left[{\begin{array}{rrr|r}a_{11}&a_{12}&a_{13}&0\\a_{21}&a_{22}&a_{32}&0\\a_{31}&a_{32}&a_{33}&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/7a0c44d6e1e35f9444dd93df21738f72af603205)
SPL Homogen ini mempunyai dua kemungkinan solusi, yaitu solusi trivial dan non trivial.
- Solusi Trivial
Contoh:
![{\displaystyle \left[{\begin{array}{rrr|r}1&2&1&0\\1&3&2&0\\2&1&2&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/efba0be824ed2ba694d290c19794037725f4417e)
Penyelesaian:
![{\displaystyle \left[{\begin{array}{rrr|r}1&2&1&0\\0&1&1&0\\0&-3&0&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/cc1e96d872945f9d11944fce7ad14f7d3e2c20b7)
B2 - B1, B3 - 2.B1
![{\displaystyle \left[{\begin{array}{rrr|r}1&2&1&0\\0&1&1&0\\0&0&3&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/842b455b43f4f5c0fdc619d3c3a74620ece56edb)
B3 + 3.B2
Det = 1 x 1 x 3 = 3
Karena det ≠ 0, solusi SPL Homogen tersebut trivial yaitu x1 = x2 = x3 = 0.
- Solusi Non Trivial
Contoh:
![{\displaystyle \left[{\begin{array}{rrr|r}1&2&1&0\\1&3&2&0\\2&1&-1&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/a32a1c1951edfd8f2c0158e8433b1490cee89026)
Penyelesaian:
![{\displaystyle \left[{\begin{array}{rrr|r}1&2&1&0\\0&1&1&0\\0&-3&-3&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/134b77b28d1804c08e6c0efb93d4195fb93de1d1)
B2 - B1, B3 - 2.B1
![{\displaystyle \left[{\begin{array}{rrr|r}1&2&1&0\\0&1&1&0\\0&0&0&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/ddab7ab277434f26f0798dff30345941f8e14840)
B3 + 3.B2
![{\displaystyle \left[{\begin{array}{rrr|r}1&0&-1&0\\0&1&1&0\\0&0&0&0\\\end{array}}\right]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/9e95d43d639dff02e8ee2603d181b83702564265)
B1 - 2.B2
Det = 1 x 1 x 0 = 0
Maka,

=

t