Any point on a plane can be named with two numbers called coordinates - an x-coordinate for the distance from the origin along the x-axis and a y-coordinate for the distance along the y-axis. The coordinate grid is divided into four quadrants by the x and y axes, and points can be plotted in the grid and identified by their coordinates and quadrant. Linear equations can be graphed by making a table of solutions and plotting the points, then drawing a straight line through them.

1. 09.28.10 ACT Opener 1. 2. 3. 4.

2. Introduction to coordinate geometry September 28, 2010

3. Coordinates Any point on the plane can be named with 2 numbers, called coordinates x- coordinate 1st number the distance from the origin along the x-axis y – coordinate The 2nd number the distance from the origin along the y-axis The pair is listed in alphabetical order (x, y) (a, b) Ordered Pair

4. The Coordinate Grid y-axis First Quadrant Second Quadrant origin x-axis Third Quadrant Fourth Quadrant

5. Points in All Quadrants (+ , +) (- , +) (- , -) (+ , -)

6. Examples Plot each point on the coordinate grid (-3, 2) (-1, -3)

7. Examples Give the coordinates and the quadrant of each point. A B A B

8. Graph Linear Equations with a Table Graph y = 2x + 3

9. Be careful with your grpahing Be Neat! Use Labels Use a straight edge

10. Examples Graph 4x – 3y = 12

11. Exit Slip Complete a table of solutions for the equation. Graph the solutions and draw a line through them. y = 7x - 5