Question

starting from 50 miles away, a car drives toward a speed checkpoint and then passes it. the car travels at a constant rate of 30 miles per hour
the distance of the car from the checkpoint is given by d=|50-30t|
at what times is the car 5 miles from the checkpoint?
could ..someone help al ittle bit in helpin me understand this

Answer 1

You want to know when the car is 5 miles from the checkpoint, that is, the car could be 5 miles before and 5 miles past the checkpoint.
This is where the absolute value part of the equation comes in, then
|50-30t| = 5
50 - 30t = 5 OR -50 + 30t = 5
-30t = -45 OR 30t = 55

solve these two equations for t to get the two different times

Answer 2

tysm!!