Question

Diketahui sistem persamaan linier:
x+y+z=-6
x-2y+z=3
-2x+y+z=9
Nilai dari 2x-3z adalah....
a.-16
b.-4
c.2
d.4
e.16
Tolong jawab sama caranya

Answer 1

Verified answer

X + y + z = - 6
x - 2y + z = 3
-------------------(-)
3y = - 9
y = - 3

x + y + z = - 6
- 2x + y + z = 9
---------------------(-)
3x = - 15
x = - 5

subtitusi
x + y + z = - 6
- 5 - 3 + z = - 6
- 8 + z = - 6
z = - 6 + 8
z = 2

nilai
2x - 3z
= 2(-5) - 3(2)
= - 10 - 6
= - 16 ( A )