Example 11.21 from Prealgebra, 11.2 Graphing Linear Equations

Graphing Linear Equations: example 11.21

Graph the equation $y = −1 .$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Solution
The equation $y = −1$ has only variable, $y .$ The value of $y$ is constant. All the ordered pairs in the table have the same $y$ -coordinate, $−1$ . We choose $0, 3,$ and $−3$ as values for $x .$

$y = −1$

$x$ $y$ $(x, y)$

$−3$ $−1$ $(−3, −1)$

$0$ $−1$ $(0, −1)$

$3$ $−1$ $(3, −1)$

The graph is a horizontal line passing through the $y$ -axis at $–1$ as shown.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Graph the equation: $y = −4 .$

How did it go?