Linear equations have four different types of slopes.

An undefined slope is a vertical line because all its points have the same x-coordinate.

Linear equations have four different types of slopes.

A zero slope is a horizontal line because all its points have the same y-coordinate.

Linear equations have four different types of slopes.

A negative slope decreases from left to right.

Linear equations have four different types of slopes.

A positive slope increases from left to right.

What is a linear equation?

1. It has one or two variables.
2. No variable in a linear equation is raised to a power greater than 1 or used as the denominator of a fraction.
3. When you find pairs of values that make the linear equation true and plot those pairs on a coordinate grid, all of the points for any one equation lie on the same line. Linear equations graph as straight lines.