Question 985409
The perpendicular line you want to find is like {{{y=-(1/3)x+b}}}.
This must contain given point  (6,3).


{{{b=y+(1/3)x}}}
{{{b=3+(1/3)*6}}}
{{{b=3+2}}}
{{{b=5}}}


Line found as  {{{y=-(1/3)x+5}}}.