## 15.1 Outline

- Solving equations with two variables
- satisfy an equation
- solution

- Cartesian coordinate system
- definition
- axis, origin, quadrants
- coordinates
- abscissa
- ordinate

- Graphing a line by plotting points
- graph of a line
- procedure

- Graphing a line by slope-intercept
- standard form
- first-degree equation
- linear equation
- independent/dependent variable
- intercepts
- y-intercept
- x-intercept

- slope
- slope-intercept form
- slope point
- special cases
- horizontal line
- vertical line

## 15.1 Essential Ideas

The first-degree equation

*y = mx + b*

where *b* is the *y*-intercept and *m* is the slope is called the slope-intercept form of the equation of a line.

Procedure for graphing a line: