M=undefined, x-int=(3,0)

  x = 3

Step-by-step explanation:

Maybe you want the equation of the line.

__

A vertical line has undefined slope. Its equation is of the form ...

  x = constant

In order for the line to go through a point with an x-coordinate of 3, the constant must be 3.

  x = 3 . . . . equation of the line

m∠5 + m∠3 = m∠1   is true.

m∠5 + m∠6 = 180 is true

m∠2 +m∠3 = m∠6   is true

m∠2 +m∠3 +m∠5 = 180   is true