1. Graphing Points & Lines Sections covered: 1.8 The Coordinate Plane 3.6 Lines in the Coordinate Plane

2. Coordinate Plane

3. Graph the following points:  (2,3)  (-8,0)  (-4,5)  (2,0)  (-6,-3)  (0,4)  (3,-7)  (0,-5)

4. What is this?

5. Slope-Intercept Form

6. Slope

7. Graphing Lines in Slope-Intercept Form  1.Use algebra to find the slope-intercept form.  2.Find the slope and the y-intercept.  3.Graph the y-intercept. where is this?  4.Graph two more points using the slope. how do we do this?  5.Connect the dots and extend the line. no small lines, because lines extend infinitely!

8. Example 1  Graph the line:

9. Example 2  Graph the line:

10. Standard Form of a Linear Equation

11. Graphing Lines in Standard Form  Find the intercepts of the line. where the line crosses both the x and y axis  To find the x-intercept, plug in zero for y, and solve for x.  To find the y-intercept, plug in zero for x, and solve for y.

12. Example 3  Transform the equation into slope-intercept form: 4x – 2y = 9

13. Example 4  Transform the equation into slope- intercept form: -5x + y = -3

14. Example 5  Graph:  6x + 3y = 12

15. Example 6  Graph:  -2x + 4y = -8

16. Point-Slope Form of a Line x 1 and y 1 are taken from the given point in the problem! This is the easiest form to start with when you’re writing an equation given a point and a slope, or two points!

17. Graph the equation: y – 3 = 2(x + 3)

18. Graph the equation: y + 4 =½(x + 4)

19. Homework…  p. 169:1-16, 33-37, 42-44  all on graph paper