Introduction to coordinate geometry

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 1 st number the distance from the origin along the x-axis y – coordinate The 2 nd 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 x -axis y-axis origin First Quadrant Second Quadrant 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 x y Point -3 2(-3) + 3 = -6 + 3 = -3 (-3, -3) -2 2(-2) + 3 = -4 + 3 = -1 (-2, -1) 2(0) + 3 = 0 + 3 = 3 (0, 3) 1 2(1) + 3 = 2 + 3 = 5 (1, 5)

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