Jawabanmu

2014-08-15T14:36:31+07:00
( x + 2 x ) + ( 2 y - y ) - ( z + 3 z ) = 3 x + y - 4 z
1 2 1
2014-08-15T14:36:39+07:00
= x + 2y -z + 2x -y +3z
=x + 2x +2y -y -z +3z
=3x +y -4z
1 5 1