SPLTV bantuin yg no. 9 dengan caranya

Keterangan :

x - y - z = 2 (1)
x + y - z = 6 (2)
2x + 3y + 2z = 10 (3)

Persamaan (2) dan (1)

x + y - z = 6
x - y - z = 2
----------------- (-)
2y = 4
y = 4/2
y = 2

Persamaan (3) dan (2)

2x + 3y + 2z = 10.....| dikali 1
x + y - z = 6.....| dikali 2

2x + 3y + 2z = 10
2x + 2y - 2z = 12
------------------------ (-)
y + 4z = -2
2 + 4z = -2
4z = -2 -2
4z = -4
z = -4/4
z = -1

Substitusi (2)

x + y - z = 6
x + 2 + 1 = 6
x = 6 - 2 - 1
x = 3

x = 3
y = 2
z = -1

HP = {(x , y , z) = (3 , 2 , -1)}

Jadi, 3x + 2y - 4z adalah 17

= 3x + 2y - 4z
= 3(3) + 2(2) - 4(-1)
= 9 + 4 + 4
= 17

Jawabannya : D. 17

Semoga membantu ;)