Answer:
x = 10 miles
Explanation:
The transmission range of the cell phone tower = 50 miles.
This tower is located 40 miles due south of a straight road.
Since the transmission range of the tower is 50 miles and it is located 40 miles away from the road, then:
the length of the section of the road within the transmission range of the tower, x = 50 - 40
= 10 miles
Therefore, x = 10 miles
This implies that any cell phone that is placed within 10 miles of the section of the road would detect the signal from the tower.