please show your work so I can know how to do this

Slope of a line between 2 points of a line given by Δy , =
difference in vertical coordinates of 2 points

ΔX difference in the horizontal coordinate of 2 points

X = 5 is a line parallel to Vertical axis:

All points along the line X=5 have the same vertical value , their difference is always f 0 ,

then:

ΔY = 0

ΔX

Y =8 : is a line parallel with horizontal axis : all points along it have the same value of X, therefore;

the difference is always 0

Δx = 0

Δy = Δy = undefined

Δx 0