3x1+4x2-x3=6
2x1-x2+6x_3=7
5x1+3x2+x3=9
|2 -1 6| =-3-6+120-5-54-8=44= Δ,
|5 3 1|
|6 4 -1|
|7 -1 6| =-6-21+216-9-108-28=44= Δx_(1),
|9 3 1|
|3 6 -1|
|2 7 6| =21-18+180+35-162-12=44= Δx_(2),
|5 9 1|
|3 4 6|
|2 -1 7|=-27+36+140+30-63-72=44= Δx_(3),
|5 3 9|
x_(1)=( Δx_(1))/ Δ=44/44=1,
x_(2)=( Δx_(2))/ Δ=44/44=1,
x_(3)=( Δx_(3))/ Δ=44/44=1.
Ответ: (1;1;1).