nilai x yg memenuhi sistem persamaan linear 2x-y=8, 2y+z=8, 3x+y+z=-3 adalah ...

2x - y = 8
2x = 8 - y
x = (8-y) / 2

2y + z = 8
z = 8 - 2y

Maka
3x + y + z = -3
3 (8-y)/2 + y + 8 - 2y = -3
24/2 - 3y/2 - y = -11
12 - 5y/2 = -11
5y/2 = 23
5y = 46
y = 9,2

x = (8-9,2) : 2
   = 1,2 : 2
   = -0,6