Question 314091
A parallel line would have the same left hand side, different right hand side.
Use the point to determine the right hand side.
{{{x+2y=4+2(6)=4+12=16}}}

{{{x+2y=16}}}
{{{2y=-x+16}}}
{{{y=-(1/2)x+8}}}
{{{drawing(300,300,-4,10,-4,10,grid(1),circle(4,6,.35),graph(300,300,-4,10,-4,10, -(1/2)x+8, -(1/2)x+9/2))}}}