2x - y + z = 5 x - 2y + 3z = 9 x + 3y + z = 0 a. Tentukan nilai x, y dan z b. Hitunglah nilai 3x + 2z Dengan cara eliminasi

2x - y + z = 5 ...(1)
x - 2y + 3z = 9 ...(2)
x + 3y + z = 0 ...(3)

Eliminasi (1) & (3)
2x - y + z = 5
x + 3y + z = 0
___________ _
x - 4y = 5 ... (4)

Eliminasi (1) & (2)
2x - y + z = 5 | × 3 → 6x - 3y + 3z = 15
x - 2y + 3z = 9 | × 1 x - 2y + 3z = 9
____________ _
5x - y = 6 ... (5)
Eliminasi (4) & (5)
x - 4y = 5 | × - 5 → -5x + 20y = -25
5x - y = 6 | × 1 5x - y = 6
____________ +
19y = -19
y = -1
subtitusi y = -1 ke (4)
x - 4y = 5
x - 4(-1) = 5
x + 5 = 5
x = 5 - 5
x = 1

subtitusi x & y ke (3)
x + 3y + z = 0
1 + 3(-1) + z = 0
1 + -3 + z = 0
z = 0 + 2
z = 2

nilai dari
3x + 2z
3(1) + 2(2)
3 + 4 = 7

semoga membantu...