1. Quick Start Expectations 1.Fill in planner and HWRS HW: p. 69, #4-8 2.Get a signature on HWRS 3.On desk: calculator, journal, HWRS, pencil, pen 4.Warm Up: next slide… back of HWRS

2. Warm Up Find the equation of the line that passes through the given points. (4, 3) and (8, 1) y = -0.5x + 5

8. As trip time increases, average speed decreases at a decreasing rate, causing a curved pattern of points. This is an inverse variation!

9. t = 500 s or st = 500 or s = 500 t Yes, this is an inverse variation! It fits the form of an inverse variation. As trip time increases, average speed decreases at a decreasing rate, causing a curved pattern of points.

10. As average speed increases, travel time decreases at a decreasing rate.

11. t = 300 s or st = 300 or s = 300 t

12. In the graph of the (s, t) data the curve drops rapidly at first and then more slowly, indicating that equal increases in speed for the trip (mph) have greater effect when the starting speed is low. A 5 mph increase from 30 to 35 is a much more significant increase than from 60 to 65. Yes, the relationship between travel time and average speed is an inverse variation because the product of time and speed is constant in this situation.

13. Begin Homework p. 69, #4-8