Answer: -2/7
|3x - 2| - 4x = 4
1) (3х - 2) - 4х = 4, if 3x - 2 >= 0
2) -(3x - 2) - 4x = 4, if 3x - 2 < 0
1)
3х - 4х = 4 + 2
-x = 6
x = -6
3х - 2 >= 0
3х >= 2
x >= 2/3 - wrong
2)
-3х + 2 - 4х = 4
-7х = 2
x = -2/7
3x-2<0
3x<2
3(-2/7)<2-right
B and C for the first two
We must look at this question in steps
The first half of the journey is travelled at 40 km/h
Half of 100km is 50 km
Using the formula
Distance = Speed x Time
Speed = Distance / Time
Time = Distance / Speed
We can work out the time:
50km / 40km/h = 1.25 hours
Next we look at the second half of the journey
50km at 80km/h
50km / 80km/h = 0.625 hours
Add together both times to work out how long the entire journey took
1.25 + 0.625 = 1.875 hours
Using the Speed formula from before
Speed = 100km / 1.875 =
53 1/3 km/h or 53.3 recurring km/h
The answer is 692.857143
Hope this helps! :)
