1. Write and graph direct variation equations.

2. 1. Solve for y : 2. Trevor ran 10 miles in 2 hours. At this rate, how far will he run in 3 hours? Determine whether or not the table shows direct variation. What is the rate as a fraction? xy 12 24 36 48 510

3.  Function: Do something to x to get y times 2 3 6

4. Slope is: how steep the line is a RATIO y over x Rise over Run m = slope … use the letter m instead of “slope” Up 2 Over 1 Pick any two points on the line

5. Last Problem the slope was 2

6. Use the direct variation function y = 3x. Complete the table for the given input values. Input, xFunction Rule y = 3x Output, y 03(0)0 13(1)3 23(2)6 33(3)9 43(4)12

7. Use the direct variation function y = 3x. Draw a scatter plot of the ordered pairs in the table and connect the ordered pairs with a straight line. Input, xOutput, y 00 13 26 39 412

8. Use the direct variation function y = 3x. Find the slope of the function.  The slope is the coefficient y = 3x of the x variable.  Slope = 3

9. This table shows ordered pairs which model direct variation. Write an equation relating the x and y coordinates.  Find the slope by calculating the ratio. Use any point.  Write the equation in the form y = mx

10. 1. Copy and complete the table 2. The table below shows ordered pairs which model direct variation. What is the slope? x01234 y036912 Input x Function RuleOutput y 0 1 2 3 4

11. Direct variation equations always look like y = mx. Which variable is a number when graphing direct variation equations? How do you find the number from a table of values?

12. Direct Variation Equations Lesson 23