Question 53644
The slope of a line is defined as {{{m=(y[2]-y[1])/(x[2]-x[1])}}}.  So just substitute your points into that equation to get {{{m=19/0}}}.  Because division by 0 is undefined, that means the slope is undefined.  You can also tell by just examining the two ordered pairs -- because they both have the same x-value, that means you have a vertical line and all vertical lines have undefined slopes.