Question 123597
x-6y=12 
6x+y=6

 first we can find y in each equation then

y = (x-12)/6 = (1/6)x-2
y = -6x+6    so coeficients of x are 1/6 and -6 then (1/6)(-6)=-1 then   

the lines are perpendicular.

(lines ax+b  and cx+d are perpendicular if only if ac=-1)