Jawabanmu

2014-09-02T18:14:10+07:00
15i-30i+14b-45b+13k+51k = -15i-31b+64k
2014-09-02T18:15:40+07:00
15i-30i+14b-45j+13k+51k
= (-15i)+14b-45j+64k
semoga membantu