Graphing Vertical Lines
The equation x = 4 is a linear equation since it can be written as
1x + 0y = 4. Let’s look at the graph.
Example 1
Graph x = 4.
Solution
Step 1 Make a table of ordered pairs that satisfy the equation.
| Each ordered pair (x, y) that satisfies
x = 4 has x-coordinate 4.
So, in the table, x is always 4.
The variable y does not appear in
the equation x = 4. So we can let y be
any real number; but x is always 4. |
|
Step 2 Plot the ordered pairs.
The points are plotted.
Step 3 Draw a line through the plotted points.
Since the x-value of each ordered pair is 4, the graph is a vertical line
4 units to the right of the y-axis.
Each point on this line represents a solution of x = 4.
Definition — Graph of a Vertical Line x = k
| The graph of an equation of the
form x = k is a vertical line
through the point (k, 0), where
k is a constant. |
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