Jawabanmu

2014-08-06T18:39:33+07:00
(9a + 12) - (7a + 14) = 9a + 12 - 7a -14 = 2a - 2
2014-08-06T18:41:30+07:00
(9a+12) - (7a+14
= (9a-7a) + (12-14)
= 2a+2                    
2 3 2