Jawabanmu

2014-09-10T14:04:42+07:00
A. a+b+c = 4x + 5 + 3x - 4 + 9x - 3
= 16x - 2

b. a-b-c = 4x + 5 - 3x + 4 - 9x + 3
= -8x + 12