Zero
Zero property of division states that zero divided by any number is equal to zero.
##0/n = 0##
A zero means a horizontal line. The ##y##-coordinate does not change no matter what the ##x##-coordinate is.
An undefined slope is when a number is divided by zero.
##n/0## = infinity or undefined
An undefined slope is a vertical line. The ##x##- coordinate never changes no matter what the ##y##-coordinate is.
