Question 1084204
The line through C (6,2) and D (1,3) 
has slope [ change in y ] / [ change in x ]
{{{ m = ( 3 - 2 ) / ( 1 - 6 ) }}}
{{{ m = 1 / (-5) }}}
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Any line perpendicular to this line 
will have slope =
{{{ m[1] = -1/m }}}
{{{ m[1] = -1/( -1/5 ) }}}
{{{ m[1] = 5 }}}
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The unknown line goes through A( -3,5 )
I can use the general point-slope formula
{{{ ( y - 5 ) / ( x -(-3) ) = 5 }}}
{{{ ( y - 5 ) / ( x + 3 ) = 5 }}}
{{{ y - 5 = 5*( x + 3 ) }}}
{{{ y - 5 = 5x + 15 }}}
{{{ 5x - y = -20 }}}
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Check:
Does it go through A( -3,5 ) ?
{{{ 5*(-3) - 5 = -20 }}}
{{{ -15 - 5 = -20 }}}
{{{ -20 = -20 }}}
OK