Jawabanmu

2014-09-12T15:08:58+07:00
9 = 3(r +2)
9 = 3r + 6
-3r = -9 + 6
-3r = -3
r = -3 : -3 
r = 1
1 4 1
2014-09-12T15:09:29+07:00
9 = 3r +6
3r + 9 = 6
3r = 6 - 9 = -3
r = -3/3 = -1