1. 12x + 8 - 7x - 10 2. 17/3x + 17 - 2/3x - 15
3. 8- 12x -10+7x
4. 9 - 9/2x - 1/2x -7
answers to choose from
-5x - 2
5x + 2
5x - 2
-5x + 2

10.8 km/hr

Step-by-step explanation:

Given that

radius of the diameter is 4 cm

Converting 4 cm to km, we have

4/100000 = 0.00004 km or 4*10^-5 km

Angular speed is given as

v = 2πr/T

Where T is, 1/n,and n is the number of revolutions

v = (2 * 3.142 * 0.00004) / (1/7000)

v = 0.00126 / 0.007

v = 0.18 km/min

This is in km/min, now we convert to km/hr as requested.

0.18 * 60 = 10.8 km/hr