Jawab:

Penjelasan dengan langkah-langkah:

(1) x + y - z = 2

(2) 3x - y + z = 6

(3) x + 2y + 3z = 7​

Pers 1 dan 2

x + y - z = 2 /3/ 3x + 3y - 3z = 6

3x - y + z = 6/1/ 3x - y + z = 6

________________________-

______________4y - 4z = 0 (4)

Pers 2 dan 3

3x - y + z = 6 /1/ 3x - y + z = 6

x + 2y + 3z = 7​ /3/ 3x + 6y + 9z = 21

___________________________-

_________________7y - 8z = -15 (5)

Pers 4 dan 5

4y - 4z = 0 /7/ 28y - 28z = 0

7y - 8z = -15/4/28y - 32z = -60

________________________ -

_____________ 4y = 60 , y = 15

Substi nilai y ke pers 4

4y - 4z = 0

4.15 - 4z = 0

- 4z = 0 - 60

z = 15

Substi nilai y dan z ke pers 1

x + y - z = 2

x + 15 - 15 = 2

x = 2