Question 1065086
<pre>
{{{drawing(400,300,-7.5,4.5,-5.5,3.5,grid(1),

circle(-1,-3,.1),
locate(-2,-3,"(-1,-3)"),red(line(-1,0,-1,-3)) )}}}

Since the point (-1,-3) is 3 units from the x-axis,
and since we know that 3-4-5 right triangles have 
a hypotenuse which is 5 units long, we draw two 
3-4-5 right triangles by using the vertical 3-unit 
line as the vertical side and draw the horizontal 
side 4 units long, like these two cases:

{{{drawing(400,300,-7.5,4.5,-5.5,3.5,grid(1),
red(line(-1,-3,3,0)), 
circle(-1,-3,.1),
locate(-2,-3,"(-1,-3)"),red(line(-1,0,-1,-3)) )}}}   {{{drawing(400,300,-7.5,4.5,-5.5,3.5,grid(1),
red(line(-1,-3,-5,0)), 
circle(-1,-3,.1),
locate(-2,-3,"(-1,-3)"),red(line(-1,0,-1,-3)) )}}}
 
Answer: (3,0) and (-5,0)

Edwin</pre>