*

**, up is positive and down is negative.**

*The vertical distance is the rise**

**, right is positive and left is negative.**

*The horizontal distance is the run** Pay close attention to the scale.

If you are given two points,

and

then you can calculate the slope algebraically using the slope formula,

This is the difference in the

*y*-values divided by the difference in the*x*-values.**Example**: Find the slope of the line passing through (1,1) and (4,−1).

**Find the slope of given line.**

Identify two points and then count to determine the rise and run.

**Find the slope of the line passing through two given points.**

*y*, or delta

*y*, divided by the change in

*x*, or delta

*x*.

**Word Problem**: While driving on the Grapevine, Joe encountered a sign warning of a 6% downgrade in the road. What does this say about the steepness of the road?

**Word Problem**: The average tuition at a public four-year college was $2,977 in 1995 and $3,489 in 1998. Find the rate at which tuition was increasing.

Since tuition depends on time, let

*x*represent time in years and let

*y*represent cost in dollars.

*y*-intercept and slope. Once a linear equation is in slope-intercept form - graphing it becomes easy.

*y*-intercept and mark off the slope from there. If you continue marking off the slope you can plot as many points as you wish.

**Example**: Graph

*y*= −2/3

*x*+ 4.

**Instructional Video**: Graphing a Line in Slope-Intercept Form

Notice that if you continue marking off the slope in this particular example you will get the

*x*-intercept, (6,0). This is very special and does not always happen.

**Graph the line**.

**Video Examples on YouTube**: