What is the equation of the line passing through (4,4) and (4,2)?

Answer 1

x = 4

Answer 2

P1 = (X1, Y1) = (4, 4)
P2 = (X2, Y2) = (4, 2)

Find the slope :

m = (Y1 - Y2) / (X1 -X2)
= (4 - 2) / (4 - 4)
= 2 / 0 -> Zero on the bottom indicates a vertical line, slope is undefined

Vertical lines are of the form : X = C, where C is a real number

Plug a point into the equation to determine C

4 = C ... this is the same with the other point as well, as you would expect with a vertical line.

So the equation is : X = C, with C = 4

X = 4

Answer 3

m = (2 - 4)/(4 - 4)
m = (-2)/0
m = undefined

ANS : x = 4