x+y+z=-2 2x+y+3z=1 x+y-z=4 nilai 1/8 xyz ?

x + y + z = -2
x + y = - z - 2 .......... (1)

x + y -z = 4
masukan persamaan (1)
-z -2 -z = 4
-2z = 6
z = -3

masukan z ke persamaan (1)
x + y = -(-3)-2
x + y = 1
y = 1-x....(2)

2x + y + 3z = 1
2x + y + 3(-3) = 1
2x+ y -9 = 1
2x + y = 10.....(3)

Subtitusikan persamaan 2 ke persamaan 3
2x + 1 - x = 10
x = 9

subtitusikan x ke persamaan 2
y = -8

x = 9
y=-8
z = -3

1/8xyz
1/8.9.(-8)(-3)
27