Horizontal lines have a slope of zero, since the "rise" is zero.
Vertical lines have an undefined slope, since the "offset" is zero, and division by zero is not allowed. ... If the slope has a value of zero, the line is horizontal, that is, it neither increases nor decreases.
• L1, and ,L2, are horizontal lines. Their slope is ,ZERO
,
• L3, and ,L4, are vertical lines. Their slope is ,UNDEFINED
The equations for the horizontal and vertical lines it is enough to equal the value of x and y to the value where we want to put our line parallel to the axis
Horizontals like L1 and L2, take a single value of y and can take any value of x
[tex]\begin{gathered} L1 \\ y=3 \end{gathered}[/tex][tex]\begin{gathered} L2 \\ y=5 \end{gathered}[/tex][tex]\begin{gathered} L3 \\ x=2 \end{gathered}[/tex][tex]\begin{gathered} L4 \\ x=6 \end{gathered}[/tex]
In summary:
Horizontal lines always have an equation of the form y = a
Vertical lines always have an equation of the form x = b
