2x+3y+z=17 2x-y-z=-1 z=-1

2x + 3y + z = 17 .....1
2x -y -z = -1 .....2
z= -1 .....3
Subtisusi z = -1 kepersamaan 2
2x -y -(-1) = -1
2x - y + 1 = -1
2x -y = -1 -1
2x - y = -2
y = 2x + 2 ... 4
Substitusi persamaan 3 dan 4 ke persamaan 1
2x + 3(2x +2) - 1 = 17
2x + 6x + 6 - 1 = 17
8x + 5 = 17
8x = 17 - 5
8x = 12
x = 12 / 8
x = 3/2
Jadi nilai x = 3/2
substisuti x = 3/2 ke persamaan 4
y = 2x + 2
y = 2 (3/2) + 2
= 3 + 2
= 5
Jadi nilai y = 5
Jadi diporeleh nilai x = 3/2, y = 5 dan z = -1