The solution should be x=5
Let's begin by listing out the information given to us:
8 am
airplane #1: x = 80870 ft, v = -450 ft/ min
airplane #2: x = 5000 ft, v = 900ft/min
1.
We must note that the airplanes are moving at a constant speed. The equation for the airplanes is given by:

2.
We equate equations 1 & 2 to get the time both airlanes will be at the same elevation. We have:

3.
The elevation at that time (when the elevations of the two airplanes are the same) is given by substituting the value of time into equations 1 & 2. We have:
( (r+2) * (2r-9)-(r^2+17r+30) )/(r+2)
none of the parenthetical operations or power operations can be simplified further, so multiplication and division first, left to right:
(2r(r+2) -9(r+2) - r^2 + 17r +30)/(r+2)
(2r^2 + 2r -9r+18 -r^2 +17r +30 )/(r+2)
(r^2 +10r +48)/(r+2)
If he runs 5 kilometers in 30 minutes, at that rate he would run 10 kilometers in an hour.
so 10 kilometers per hour is his speed
Answer:
73
Step-by-step explanation: