Jawabanmu

2014-09-03T20:45:43+07:00
1. (13a-8b) + (12a+9b) => 13a+12a-8b+9b = 25a+b
2. (15i+14b+13k) + ( -30i - 40j + 51k ) = 15i - 30i + 13k + 51k + 14b - 40j = -15i + 64k + 14b - 40j

2014-09-03T20:54:15+07:00
1. 13a+8b+12a+9b= (13a+12a)+(8b+9b)= 25a+17b
2. 15i+14b+13k-30i-45j+51k= (15i-30i)+(14b-45b)+(13k-51k) = -15i-31b-38k