Question 1018278
This is the way it works:
<a href="https://www.youtube.com/watch?v=VDKztVZUgnM">Equation of Line Through Two Points</a>


Once that done, you want to change from form y=mx+b into Ax+By=C.  That should be simple algebra.  Imagine you have {{{y=(n/d)x+b}}}.
{{{dy=nx+db}}}
{{{dy-nx=db}}}
{{{-nx+dy=db}}}
or
{{{nx-dy=-db}}}