Question 1209062
<pre>

This is really a look-and-see problem if you have graph paper.
Let's call the midpoint M(5,-4).  Notice that M is 2 units left
and 2 units down from B. Since M is the midpoint of AB, you know 
that A has to be two units left and 2 units down from M. The
green line MB is half of AB.

{{{drawing(600,600,-5,10,-10,5, grid(1),
locate(5.08,-4.05,"M=(5,-4)"), locate(7.08,-2.05,"B=(7,-2)"),
circle(5,-4,.15), circle(7,-2,.15), circle(5,-4,.12), circle(7,-2,.12),
circle(5,-4,.1), circle(7,-2,.1),green(line(5,-4,7,-2))   


)}}}

So let's redraw the graph, and you can locate A by observing what point
is 2 units left and 2 units down from M. We'll draw the lower half of AB,
which is AM.  So what are the coordinates of A?  I don't need to tell you,
right?  You can look and see! 


{{{drawing(600,600,-5,10,-10,5, grid(1),
locate(5.08,-4.05,"M=(5,-4)"), locate(7.08,-2.05,"B=(7,-2)"),
circle(5,-4,.15), circle(7,-2,.15), circle(5,-4,.12), circle(7,-2,.12),
circle(5,-4,.1), circle(7,-2,.1), circle(3,-6,.1), circle(3,-6,.15), circle(3,-6,.12), locate(3.08,-6.05,"A=(?,?)"),green(line(3,-6,7,-2))     


)}}}

Edwin</pre>