1. Lesson 5.2 Direct Variation Direct variation y = kx Where k is the constant of variation.

2. Name the constant of variation for the equation. Then find the slope of the line that passes through the pair of points. Slope formula Simplify. Answer: The constant of variation is 2. The slope is 2.

3. Name the constant of variation for the equation. Then find the slope of the line that passes through the pair of points. Slope formula Simplify. Answer: The constant of variation is –4. The slope is –4.

4. Name the constant of variation for the equation. Then find the slope of the line that passes through the pair of points. a. Answer: constant of variation: 4 ; slope: 4

5. Answer: constant of variation: –3 ; slope: –3 Name the constant of variation for the equation. Then find the slope of the line that passes through the pair of points. b.

6. Step 1 Write the slope as a ratio. Step 2 Graph (0, 0). Step 3 From the point (0, 0), move up 1 unit and right 1 unit. Draw a dot. Step 4 Draw a line containing the points.

7. Answer:

8. Step 1 Write the slope as a ratio. Step 2 Graph (0, 0). Step 3 From the point (0, 0), move down 3 units and right 2 units. Draw a dot. Step 4 Draw a line containing the points.

9. Answer:

10. Suppose y varies directly as x, andwhen Write a direct variation equation that relates x and y. Find the value of k. Direct variation formula Replace y with 9 and x with –3. Divide each side by –3.

11. Simplify. Answer: Therefore,

12. Use the direct variation equation to find x when Direct variation equation Answer: Therefore, when Replace y with 15. Divide each side by –3. Simplify.

13. Suppose y varies directly as x, andwhen a. Write a direct variation equation that relates x and y. b. Use the direct variation equation to find x when Answer: –15 Answer: