Factor out 8 and then facotr and u get
8/9(9x+1)(9x-1
This question involves the concepts of average speed, distance, and time.
The average speed of the family is "2.5 mi/hr".
<h3>AVERAGE SPEED</h3>
The average speed is defined as the ratio of the total distance covered with the total time taken to cover it.

where,
- s = distance covered = 2.5 miles
- t = total time taken = 1 hour
- v = average speed = ?
Therefore,

v = 2.5 mi/hr
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Increase in sea water pollution
Answer A is incorrect
A crest is just one point. It is not the distance between 2 crests.
B is incorrect
A trough is just 1 point. It is not the distance between 2 troughs.
C is incorrect.
the amplitude measures the height of a crest from the middle of the wave to the crest (or trough).
D is the correct answer. That is the distance between 2 crests or 2 troughs