### Linear Equations and Graphing

In this video, step-by-step instructions on how to graph points on a coordinate plane are presented.

## Graphing Points on a Coordinate Plane

#### Graphing on the coordinate plane is a way to visualize relationships between two quantities.

The diagram below shows the different parts of the coordinate plane.

The point where the x-axis and y-axis intersect is called the origin.

Notice that x-values to the right of the y-axis are positive and x-values to the left of the y-axis are negative. Similarly, y-values above the x-axis are positive and y-values below the x-axis are negative

#### An ordered pair of numbers is used to locate any point on the plane.

An ordered pair is enclosed in a pair of parentheses with the first number representing a location on the x-axis, the x-coordinate, and the second number representing a location on the y-axis, the y-coordinate. To locate a point on the coordinate plane, do the following:

**3. **The second number is the y-coordinate.

1. |
Start at the origin. | |

2. |
The first number is the x-coordinate. | |

If it is positive, move to the right the appropriate number of units. | ||

If it is negative, move to the left the appropriate number of units. | ||

If it is positive, move up the appropriate number of units. | ||

If it is negative, move down the appropriate number of units. |

Look at the coordinate grid below.The ordered pair for point A is $(3, -2)$. To locate point A, we move three units to the right and two units down. Also shown on the coordinate plane are points B, C, D, and E.

#### A little history:

When you graph points on a coordinate plain (also called a Cartesian coordinate system), you are using the work of René Descartes. Descartes (1596 – 1650) was a French mathematician, scientist and philosopher. His work provided the first systematic link between geometry and algebra.