1. §2.5 Model Direct Variation CA Standard 2.0 Students solve systems of linear equations and inequalities (in two or three variables) by substitution, with graphs, or with matrices.

2. Warm Up Write an equation of the line that passes through the point and satisfy the given condition.

3. Write an equation of the line that passes through (5,-6) and is (a) parallel to, and (b) perpendicular to, the line

4. Direct Variation The equation represents direct variation between x and y, and y is said to vary directly with x, where a is the constant of variation.

5. Examples of Direct Variation The graphs of direct variation must go through (0,0).

6. EX1: Write and graph a direct variation equation that has (-3, -9) as a solution.

7. EX2: Write and graph a direct variation equation that has the given ordered pair as a solution. a. (3, -9) b. (-7, 4)

8. EX3: The variable x and y varies directly. Write an equation that relates x and y. Then find x when y=-2. a. x=6, y=-8

9. EX3: The variable x and y varies directly. Write an equation that relates x and y. Then find x when y=-2. b. x=12, y=-8

10. Homework #19 Pg. 109 #1-27 odd, 38-40