Question 622291
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
Find a general form equation for the line through the pair of points. 
(4,-1) and 
(4,5).  m = -6/0, yes undefined slope.  Good work.
Vertical Line x = 4
{{{drawing(300,300,   -6, 6, -6, 6,  green(line(4,6,4,-6))  , grid(1),

graph( 300, 300, -6, 6, -6, 6))}}}