3y - 15 +2y+13=4y-9-6y

3y - 15 +2y+13=4y-9-6y 3y + 2y - 4y + 6y = -9 + 15 - 13 7y = -7 /: 7 y = -1

3y-15+2y+13=4y-9-6y 5y-2=-2y-9 5y+2y=-9+2 7y=-7 y=-1

3y-15+2y+13=4y-9-6y 3y+2y-4y+6y=-9+15-13 7y=-9+2 7y=-7/:7 y=-1