Menggunakan metode gabungan (eliminasi dan substitusi)​

Penjelasan dengan langkah-langkah:

pers 1 ) x + 2y + z = 11

pers 2) 3x + y +2z = 14

pers 3) 2x – 3y +5z = 13

eliminasi pers 1 dan 2 :

x + 2y +z = 11 | x 2 2x + 4y + 2z = 22

3x + y + 2z = 14 | x 1 _ ==> 3x + y + 2z = 14 _

-x + 3y = 8

eliminasi pers 2 dan 3 :

2x – 3y +5z = 13 | x 2 4x – 6y + 10z = 26

3x + y + 2z = 14 | x 5 _ ==> 15x + 5y + 10z = 70 _

– 11x – 11y = – 44 | : -11

x + y = 44

subsitusi hasil eliminasi pers 1 dan 2 ke hasil eliminasi 2 dan 3:

-x + 3y = 8 == > x = 3y – 8

x + y = 44

=> 3y – 8 + y = 44

=> 4y = 52

=> y = 13

x = 3y – 8

=> x = 3(13) – 8

=> x = 31

masukan nilai x dan ya ke pers 1 :

x + 2y + z = 11

=> 31 + 2(13) + z = 11

=> 31 + 26 + z = 11

=> 57 + z = 11

=> z = 11 – 57

=> z = -46