Question 1088737
First find qr.
Use the points to get the slope.
{{{m[qr]=(4-1)/(-3-(-5))=3/(-3+5)=3/2}}}
Perpendicular lines have slopes that are negative reciprocals,
{{{m[qr]*m[p]=-1}}}
{{{(3/2)*m[p]=-1}}}
{{{m[p]=-2/3}}}
Use the point-slope form of a line with point p,
{{{y-(-9)=-(2/3)(x-9)}}}
{{{y+9=-(2/3)x+6}}}
{{{y=-(2/3)x-3}}}
{{{highlight(y=-(2x+9)/3)}}}
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*[illustration dfv10.JPG].
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