## Key Concepts

**Find the slope from a graph**- Locate two points on the line whose coordinates are integers.
- Starting with the point on the left, sketch a right triangle, going from the first point to the second point.
- Count the rise and the run on the legs of the triangle.
- Take the ratio of rise to run to find the slope, \(m=\frac{\text{rise}}{\text{run}}\)

**Slope of a Horizontal Line**- The slope of a horizontal line, \(y=b\), is 0.

**Slope of a Vertical Line**- The slope of a vertical line, \(x=a\), is undefined.

**Slope Formula**- The slope of the line between two points \(\left({x}_{1},{y}_{1}\right)\) and \(\left({x}_{2},{y}_{2}\right)\) is \(m=\frac{{y}_{2}-{y}_{1}}{{x}_{2}-{x}_{1}}\)

**Graph a line given a point and a slope.**- Plot the given point.
- Use the slope formula to identify the rise and the run.
- Starting at the given point, count out the rise and run to mark the second point.
- Connect the points with a line.

## Glossary

### slope of a line

The slope of a line is \(m=\frac{\text{rise}}{\text{run}}\). The rise measures the vertical change and the run measures the horizontal change.