Jawabanmu

2014-08-29T17:19:25+07:00
(2y + 15z) - (4y - 8) = 2y + 15z - 4y + 8
=2y - 4y +15z + 8
= -2y + 15z + 8
7 4 7
2014-08-29T17:19:42+07:00
= (2y + 15z) - (4y - 8 )
= 2y + 15z - 4y - 8
= 2y - 4y + 15z - 8 
= -2y + 15z - 8
9 3 9