Jawabanmu

2014-09-03T15:16:11+07:00
4 (3x+5y-7) dari 3(5x+4y-8)
= 3(5x+4y-8) - 4(3x+5y-7)
=15x+12y-24-12x-20y+28
=15x-12x+12y-20y-24+28
=3x-8y+4

2014-09-03T15:20:05+07:00
3(5x+4y-8) - 4(3x+5y-7)
= 15x + 12y - 24 - 12x - 20y + 28
= 15x - 12x + 12y - 20y - 24 +28
= 3x + (-8y) + 4
= 3x - 8y + 4