nilai y yang memenuhi sistem persamaan [tex]x - y + z = 6 \\ 2x + y - z = 0 \\ x + 3y + 2z = 5[/tex] adalah a.-3 d.2 b.-1 e.3 c.1

x - y + z = 6
2x + y - z = 0
-------------------(+)
3x = 6
x = 2

2x + y - z = 0 |×2
x + 3y + 2z = 5
maka
4x + 2y - 2z = 0
x + 3y + 2z = 5
----------------------(+)
5x + 5y = 5

subtitusi
5x + 5y = 5
5(2) + 5y = 5
10 + 5y = 5
5y = 5 - 10
5y = - 5
y = - 1

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

nilai y yg memenuhi = - 1 ( B )