Write an equation of the line in slope-intercept form.

y=

To find the equation for a line in slope-intercept form, we need to find the slope and the y-intercept.

The y-intercept is easy to find. It's just the value of when . In this case, the y-intercept is since the line goes through the origin.

To find the slope, we use the slope formula, where and are two known points. In this case, we'll use the only two points we have: and

Finally, we put it all together in slope-intercept form, where is the slope and is the y-intercept.

the function makes a strait line horizontally with no x intercept but a y intercept at 9.