It would be 8r+72.
8(r+9) = (8*r)+(8*9)
ANSWER
The average speed is 7m/s.
EXPLANATION
If the dot ran from -66 to -17, then the distance covered is

The average speed

Substitute

Simplify;

- linear pairs are supplementary, meaning they add up to 180°
5x + 9 + 3x + 11 = 180
8x + 20 = 180
8x = 160
x = 20
- now plug in.
angle 1: 5(20) + 9 = 100 + 9 = 109°
angle 2: 3(20) + 11 = 60 + 11 = 71°
60% of 90 = 54!
I hope I helped!
600 km. You're driving 100km every hour, 6 x 100 = 600.