1. 5.3 – direct variation Textbook pg. 301 Objective:
The student will find direct variation in order to recognize linear functions.

2. Direct variation: a linear function (has a slope) that specifically goes through the origin - spoken as “when y varies directly with x” - equation looks like y = kx constant of variation: k, the slope ( 𝑦 𝑥 )
Is it direct variation? If so, what is the constant of variation?
1) y = 4x 2) 2x = 8y 3) x – 2y = 6

3. Graphing Direct Variation:X Y
5) y = 2x

4. Solving Direct Variation:
Don’t forget  k = 𝑦 𝑥
Find k, write a direct variation equation, then find the missing variable.
6) Suppose y varies directly with x, and y = 35 when x = 5. Write an equation and find y when x = 9.

5. Find k, write a direct variation equation, then find the missing variable.
7) Write an equation if y varies directly with x and y = 4.5 when x = 0.5. Then find x when y = 10.

6. Name Date Period 5.3 – pg. 304 #9-12, 15-18, 23