pakai cara yaa mksih sblmx

2x+y=4 |×1
x+2z=3 |×2
__________
2x+y=4
2x+4z=6
________(-)
y-4z=-2

3y-z=5 |×1
y-4z=-2 |×3
_________
3y-z=5
3y-12z=-6
________(-)
11z=11
z=1