## Objective:

**To graph horizontal and vertical lines.**

## Vocabulary:

**Horizontal**- goes left to right (*think horizon*)**Isolate**- get it by itself (alone).**Vertical**- goes up and down.

## Notes:

- The graph of
*x = a*is a*vertical*line that goes through point*a*on the x-axis. - The graph of
*y = b*is a*horizontal*line that goes through point*b*on the y-axis.

## Examples:

1. Sketch the graph of x = 3.When we graph in a coordinate plane we have two variables, x and y.

For the equation x = 3, x is

*ALWAYS*3. It doesn't make any difference what y is, x can only be 3.

The equation, x = 3, doesn't tell us anything about y. It doesn't restrict y at all, so y can be any number.

Plot a few points making each x-coordinate 3 and varying the y-coordinate. Some examples are (3, −4), (3, −1), (3, 2), and (3, 5).

Draw a line with arrows through the points you plotted. Make sure to label the line.

2. Sketch the graph of y = −4.

For the equation y = −4, y is

*ALWAYS*−4. It doesn't make any difference what x is, y can only be −4.

The equation y = −4 doesn't tell us anything about x. It doesn't restrict x at all, so x can be any number.

Plot a few points with the y-coordinate always -4, and vary the x-coordinate. Some examples are (−4, −4), (−2, −4), (0, −4), and (3, −4).

Draw a line with arrows through the points you plotted. Make sure to label the line.

### Hint:

Graphing these types of problems is easy if you remember the following:- If the problem is
*x = __*then it cuts through the*x*-axis. - If the problem is
*y = __*then it cuts through the*y*-axis.