Question 1112409
<pre>
Plot the given point B(3,5) and a vertical line through it:
{{{drawing(400,400,-7,7,-7,7, graph(400,400,-7,7,-7,7),green(line(3,-10,3,10)),
circle(3,5,.1),locate(3.1,5,"B(3,5)")  )}}}

Next draw several possibilities for A(x,3), for instance
A(-4,3), A(-1,3), A(1,3), and A(5,3)

{{{drawing(400,400,-7,7,-7,7, graph(400,400,-7,7,-7,7),green(line(3,-10,3,10)),
circle(3,5,.1),locate(3.1,5,"B(3,5)"),
circle(-4,3,.1),circle(-1,3,.1),circle(1,3,.1),circle(5,3,.1),
locate(-4+.1,3,"A(-4,3)"),locate(-1+.1,3,"A(-1,3)"),locate(1.1,3,"A(1,3)"),locate(5.1,3,"A(5,3)")


  )}}} 

Draw a line through them:

{{{drawing(400,400,-7,7,-7,7, graph(400,400,-7,7,-7,7),green(line(3,-10,3,10)),
circle(3,5,.1),locate(3.1,5,"B(3,5)"),
circle(-4,3,.1),circle(-1,3,.1),circle(1,3,.1),circle(5,3,.1),
locate(-4+.1,3,"A(-4,3)"),locate(-1+.1,3,"A(-1,3)"),locate(1.1,3,"A(1,3)"),locate(5.1,3,"A(5,3)"), blue(line(-10,3,10,3))


  )}}}  

Now you can see that the only value of x is the value where the
blue line crosses the green vertical line, which is at A(3,3)

{{{drawing(400,400,-7,7,-7,7, graph(400,400,-7,7,-7,7),green(line(3,-10,3,10)),
circle(3,5,.1),locate(3.1,5,"B(3,5)"),
circle(3,3,.1),
locate(3.1,3,"A(3,3)"), blue(line(-10,3,10,3))


  )}}} 

Edwin</pre>