Nilai x+y+z yang memenuhi SPLTV x+2y+3z=5,x+y+z=-1,dan 3x-2y-z=-9 adalah....

x + 2y + 3z = 5
x = 5 - 2y - 3z

x + y + z = -1
5 -2y - 3z + y + z = -1
5 -y - 2z = -1
y + 2z = 6
y = 6 - 2z

3x - 2y - z = -9
3(5-2y - 3z) - 2y - z = -9
15 - 6y - 9z - 2y - z = -9
- 8y - 10z = -24
8y + 10z = 24
8(6-2z) + 10z = 24
48 - 16z +10z = 24
6z = 24
z = 4

y = 6 - 2z
y = 6 - 2(4)
y = -2

x = 5 - 2y - 3z
x = 5 -2(-2) - 3(4)
x = -3

Jadi,
x = -3
y = -2
z = 4