Hp dari sistem persamaan x+3y-z= 3 x+2y+3z= -2 x+y-z=1

x + 3y - z = 3
x + 2y + 3z = - 2
-------------------------(-)
y - 4z = 5 ... pers 1

x + 2y + 3z = - 2
x + y - z = 1
------------------------(-)
y + 4z = - 3 ... pers 2

pers 1 & 2
y - 4z = 5
y + 4z = - 3
----------------(-)
- 8z = 8
z = - 1

y - 4z = 5
y - 4(-1) = 5
y + 4 = 5
y = 5 - 4 = 1

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