1. Identifying Horizontal and Vertical Lines

2. Vertical and horizontal lines can be hard to spot!
Find the line!
Vertical and horizontal lines can be hard to spot!

3. Horizontal lines Horizontal lines always have equations in the form
y = a constant
Makes sense since y = mx + b
and the slope of a horizontal line is 0
y = 0( x ) -9
y = - 9

4. Find the line!

5. Vertical lines Vertical lines are just plain weird!
They don’t really fit the equation y = mx + b
If you were skiing, they’d be cliffs!
Their slopes are undefined.
You just have to remember the format
x = a constant
x = - 3

6. When asked for the equation of a line in a graph
If you can’t see a line it’s probably a horizontal or vertical line.
Look around the edge of the graph paper for protrusions!
Horizontal lines are always y = a constant.
Vertical lines are always x = a constant.