perpendicular angle so the slope is the opposite reciprocal: 1/6 
[tex]y =  \frac{1}{6}  + b[/tex]
plug in x and y values of given point 
[tex] - 3 =  \frac{1}{6} (12) + b[/tex]
find b
b = - 5
rewrite equation with b and slope values
[tex]y =  \frac{1}{6} x - 5 [/tex]