Answer:

Step-by-step explanation:
we know that
The diagonal of a cube is equal to

where
b is the length of an edge of the cube
we have

substitute


100=1,478,300
1000=1,478,000
10,000=1,470,000
Answer:
a) ~10.58 km/h
b) 45 min
c) 15 km/h
Step-by-step explanation:
a) 45km for 4 hours and 15min (4.25 hours) = 45 / 45.25 ~= 10.58 km/h
b) From 4:15 to 5 = 45min
c) 45km for 3 hours (5:00 to 8:00) = 45 / 3 = 15 km/h
NOTE!
The author actually wanted the answer on A) to be 10 km/h and the journey to be 4.5 hours (4 hours 30min) but instead they made it 4.25 (as shown on the graph, since 1 square is 30 minutes).
An equation which shows a valid step that can be used to solve the given mathematical equation is ![(\sqrt[3]{2x - 6})^3 = (-\sqrt[3]{2x + 6})^3](https://tex.z-dn.net/?f=%28%5Csqrt%5B3%5D%7B2x%20-%206%7D%29%5E3%20%3D%20%28-%5Csqrt%5B3%5D%7B2x%20%2B%206%7D%29%5E3)
<h3>What is an equation?</h3>
An equation simply refers to a mathematical expression that can be used to show the relationship existing between two (2) or more numerical quantities.
In this exercise, you're required to show a valid step which can be used to solve the given mathematical equation. Since both equations are having a cube root, the first step is to take the cube of both sides.
Take the cube of both sides, we have:
![\sqrt[3]{2x - 6} + \sqrt[3]{2x + 6} = 0\\\\(\sqrt[3]{2x - 6})^3 + (\sqrt[3]{2x + 6})^3 = 0^3\\\\(\sqrt[3]{2x - 6})^3 = (-\sqrt[3]{2x + 6})^3](https://tex.z-dn.net/?f=%5Csqrt%5B3%5D%7B2x%20-%206%7D%20%2B%20%5Csqrt%5B3%5D%7B2x%20%2B%206%7D%20%3D%200%5C%5C%5C%5C%28%5Csqrt%5B3%5D%7B2x%20-%206%7D%29%5E3%20%2B%20%28%5Csqrt%5B3%5D%7B2x%20%2B%206%7D%29%5E3%20%3D%200%5E3%5C%5C%5C%5C%28%5Csqrt%5B3%5D%7B2x%20-%206%7D%29%5E3%20%3D%20%28-%5Csqrt%5B3%5D%7B2x%20%2B%206%7D%29%5E3)
Read more on equations here: brainly.com/question/13170908
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