Jawabanmu

2014-09-01T14:57:03+07:00
x-y-(6x+4)=x-y-6x-4
               =-5x-y-4

2014-09-01T15:08:52+07:00
( x -y ) - ( 6x + 4) = x - 6x -y - 4 = -5x - y - 4