Tentukan nilai [tex]2x + y = [/tex]

x+6 + 3x+6y = 12
4x + 6y + 6 = 12
(4x + 6y = 6)/2
2x + 3y = 3 ........ (1)

2x + 4y = 8 ........ (2)

(1) dkurangi (2)

2x + 3y = 3
2x + 4y = 8
----------------- -
- y. = -5
y = 5

2x+3(5)=3
2x+15=3
2x=-12
x= -6

subs x dan y ke soal