One "x" value mapped to 2 "y" values. This is NOT a function, and therefore has an UNDEFINED slope.
Answer by amalm06(224) (Show Source): You can put this solution on YOUR website! Slope=m=Δy/Δx=(-3-2)/(5-5)=-5/0
The slope is undefined. This is a vertical line passing through (5,2) and (5,-3). The angle it makes with the x-axis is 90 degrees and tan(90) is undefined.