It could be all it could be one but the true answer is I’m not sure which one
Answer: Choice B) 
We have some value m and we're squaring it to get 
To undo this and isolate m, we apply the square root to both sides
There are two solutions here. This is similar to how there are two solutions in something like 
(those two solutions being x = 5 and x = -5). Squaring any negative number leads to a positive result because
negative times negative = positive.
I don’t really know exactly what you’re asking but if you’re asking what is most practical, it would be #4
Answer:
Morning's average rate = 50 mph, and Afternoon's average rate = 25 mph.
Step-by-step explanation:
Suppose he drove 150 miles for X hours, then his average rate in the morning was (150/X) mph.
Given that he spent 5 hours in driving.
And he drove 50 miles for (5-X) hours, then his average rate in the afternoon was 50/(5-X) mph.
Given that his average rate in the morning was twice his average rate in the afternoon.
(150/x) = 2 * 50/(5-x)
150/x = 100/(5-x)
Cross multiplying terms, we get:-
150*(5-x) = 100*x
750 - 150x = 100x
750 = 100x + 150x
750 = 250x
x = 750/250 = 3.
It means he spent 3 hours in the morning and 2 hours in the afternoon.
So morning's average rate = 150/3 = 50 mph.
and afternoon's average rate = 50/(5-3) = 25 mph.
