1. Warm-Ups 1. Who developed the Cartesian coordinate system? 2. What was his nationality? 3. What academic discipline, other than math, was he known for? 4. By introducing the system, what two areas of mathematics did he bring together? 5. Where do the x-axis and y-axis intersect?

2. Warm-Ups 1. Who developed the Cartesian coordinate system? 2. What was his nationality? French 3. What academic discipline, other than math, was he known for? Philosophy 4. By introducing the system, what two areas of mathematics did he bring together? 5. Where do the x-axis and y-axis intersect? Rene Descartes algebra & geometry origin or (0, 0)

3. Read Read Section 7-3, Part 1 on p.313.

4. Table of Values Example 1: Graph 2y + 6x = 4 Solve for y. -6x 2y = -6x + 4 22 y = -3x + 2 xy 0-3(0) + 2 = 2 1-3(1) + 2 = -1 2-3(2) + 2 = -4

5. Try This Graph 3y - 12 = 9x using 3 points

6. Definitions Read Section 7-3, Part 2 on p.314. Copy the Definitions into your notes.

7. Standard Form (Linear Equations) Ax + By = C A, B, and C are constants.

8. Cover-Up Method (use when in standard form) Graph 2x - 4y = 8 Cover up the x-term & solve for y. That is the y-intercept. y = -2 Cover up the y-term & solve for x. That is the x-intercept. x = 4 Example 2

9. Try This Graph 3x + 2y = 6

10. Horizontal & Vertical Lines for constants a and b, the graph of y = b is a horizontal line with a y-intercept of b. the graph of x = a is a vertical line with an x-intercept of a.

11. Try This Graph x = -3 Graph y = 1

12. SLOPE slope To find the slope between (x 1, y 1 ) & (x 2, y 2 ): always go left to right

13. Example 3 #1: Plot the points. #2: Draw the line. What is the rise? (L to R) Graph the line containing the points (2, 1) and (4, 3) and find the slope. What is the run? (L to R) 3-1 = 2 4-2 = 2

14. Try This Graph the line containing (-2, 3) and (3, 5) and find the slope. Graph the line containing (0, -3) and (-3, 2) and find the slope.

15. Example 4 Find the slope of the line containing the points (2, 1) and (7, 3). Stack & Subtract (7, 3) - (2, 1) 5, 2 5 x1x1 y1y1 x2x2 y2y2

16. Try This Find the slopes of the lines containing these points. (2, 2) and (8, 9) (5, -11) and (-9, 4)

17. Horizontal & Vertical Lines Read Examples 3 & 4 on p.320. Slope for Horizontal & Vertical Lines A horizontal line has slope 0. A vertical line has undefined slope.

18. Try This Find the slopes of the lines containing these points. (9, 7) and (3, 7) (4, -6) and (4, 0) 0 undefined

19. Assignment p. 316 #1, 2, 3, 20, 21, 28, 34, 37 p. 321 #1-4 (do not draw), 5-8, 11-18, 21-24, 29, 30