Learn about the equation of a line. After you finish this lesson, view all of our Pre-Algebra lessons and practice problems.

**Equation of a Line (Slope-Intercept Form)**

where *m* = slope and *b* = y-intercept.

To find the slope, use the slope formula:

## Examples of Equation of a Line

### Example 1

First, let’s determine the coordinates of the points

and

Then, solve for the slope

Slope-intercept form is

Where = slope and = -intercept

Now, our y-interecept is

Substitute the given and we have

### Example 2

First, let’s determine the coordinates of the points

and

Then, solve for the slope

Slope-intercept form is

Where = slope and = -intercept

Now, our y-interecept is

Substitute the given and we have

## Video-Lesson Transcript

In this lesson, we’ll review the equation of a line and go over the slope-intercept form which is the most common equation of a line.

It’s called slope-intercept form for a very specific reason.

When we look at the equation, we will know what our slope is and its intercept.

Intercept is where a line segment intersects the axis. The -intercept is the point where the line segment crosses or touches the -axis.

Slope-intercept form is

Where slope and -intercept

Our formula for slope is

Let’s look at the graph.

Then count the change in and from the origin with coordinates.

So we have

Now, let’s refer back to the graph and look where the line intersects the -axis. Meaning, find the point where the line meets the – axis and where the -axis is .

Now, our -interecept is .

So now .

Now, we’re ready to write the slope-intercept form.

Substitute the given and we have

So our slope-interecept form is

Again, the slope-intercept form is

Where slope and -intercept.