David's airplane trip took 3.8 hours. For one-half of that time, the airplane flew at a speed of 680 miles per hour, and for the rest of the time, it flew at a speed of 740 miles per hour. What distance did David travel?

2,698 mi

Step-by-step explanation:

3.8 hr × 1/2 = 1.9 hr

680 mi/hr × 1.9 hr = 1,292 mi

740 mi/hr × 1.9 hr = 1,406 mi

1,292 mi + 1,406 mi = 2,698 mi

the direct variation says that:

then the equation is of the form is given by:

            where k is the constant variation.

from the given table:

consider any value of x and m(x)=y

x = 2 and m(x)=y = 3

substitute these value in [1]; we have;

divide both sides by 2 we get;

⇒

check:

put x = -1 and m(x) = -1.5

substitute in the equation:

-1.5 = -1.5                   true

therefore, the function m(x) represents a direct variation

graph of this function as shown below: