Jawabanmu

2014-09-10T19:18:07+07:00
1. (11x - 13y + z ) - (10x - 13y - z)
11x - 13y + z - 10x + 13y + z
11x - 10x - 13y + 13y + z + z
= 1x + 2z

2. (3x + 2y) - (4x + y + 9z)
3x + 2y - 4x - y - 9z
3x - 4x + 2y - y - 9z
= -x + y - 9z

3. 3x + 4x - 2xy - 2x - x + 2xy
7x - 2x - x - 2xy + 2xy
= 4x