No 14 helpp me hari ni dikumpul

x + y + z = 3
3y - x = 21
2x + y + 2z = - 5

3y - x = 21
- x = 21 - 3y
x = - 21 + 3y
x = 3y - 21

x + y + z = 3
3y - 21 + y + z = 3
4y + z = 3 + 21
4y + z = 24

2x + y + 2z = - 5
6y - 42 + y + 2z = - 5
7y + 2z = - 5 + 42
7y + 2z = 37

4y + z = 24|× 2
7y + 2z = 37|× 1

8y + 2z = 48
7y + 2z = 37
_________ —
y = 11

x = 3y - 21
x = 33 - 21
x = 12

4y + z = 24
44 + z = 24
z = 24 - 44
z = - 20

Jawaban : a. 12

Maaf Kalau Salah