Answer:

Step-by-step explanation:
Let suppose that airliners travel at constant speed. The equations for travelled distance of each airplane with respect to origin are respectively:
First airplane

Where t is the time measured in hours.
Since north and west are perpendicular to each other, the staight distance between airliners can modelled by means of the Pythagorean Theorem:

Rate of change of such distance can be found by the deriving the expression in terms of time:

Where
and
, respectively. Distances of each airliner at 2:30 PM are:


The rate of change is:


I want to say A because 168 tenths should equal 168 thousandths
Answer:
4.5 ft
Step-by-step explanation:
Let us assume the height of the taller brother be x
And, the height of the shorter brother be y
Now according to the question
x + y = 10.33
x - y = 0.833
Now solve these two equations
2x = 11.666
x = 5.833
y = 10.33 - 5.83
= 4.5 ft
X=-3
because
-4x=21-9
-4x= 12 divide both sides
x=-3
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