Jawabanmu

2014-09-04T21:42:17+07:00
2014-09-04T22:11:08+07:00
1.) 13a-8b + 12a + 9b
13a + 12a -8b +9b
25a + b

2.) 15i+14b+13k + (-30i-45+51k)
15i+14b+13k -30i-45+51k
15i -30i + 13k + 51k +14b -45
-15i + 64k + 14b -45

semoga membantu :))