let's solve the first for y...
3x+6y=8
6y=-3x+8
y=(-x/2)+4/3, the other line is: y=2x–8
notice that (-1/2)(2)=-1 so these lines are perpendicular to one another...
(rule for lines to be perpendicular their slope must have this relationship:
m1*m2=-1 )
Since that relationship is true, these two lines are perpendicular to one another.
