Question 106047
To find a line perpendicular to the line going throught the 2 points,
we need to find its slope first. 
{{{m=(y[2]-y[1])/(x[2]-x[1])}}}
for the two points (0,5) and (-3,-4), 
{{{m=(-4-5)/(-3-0)}}}
{{{m=(-9)/(-3)}}}
{{{m=3}}}
The line going through (0,5) and (-3,-4) has a slope of 3. 
Perpendicular lines have a relationship between their slopes as follows,
{{{m[1]*m[2]=-1}}}
In this case,
{{{3*m[2]=-1}}}
{{{m[2]=-(1/3)}}}
Therefore your perpendicular line equation is,
{{{y=mx+b}}}
{{{y=-(1/3)x}}}
where b=0 for simplicity. 
{{{drawing( 300, 300, -6, 6, -6, 6,grid( 1 ),circle( 0, 5, .2 ),
circle(-3,-4,.2),green(line( 0,5,-3,-4)),blue(line(-10,3.33,10,-3.33)))}}}