Answer:

Step-by-step explanation:
A linear function has the following format:

In which a is the slope(rate of change) and b is the y-intercept, that is, the value of y when x = 0.
Rate of change of 3
This means that 
So

A solution at (6, 12).
This means that when x = 6, y = 12. So



The linear function is:

You gave us the speed and the frequency, and you need the wavelength.
You were also nice enough to remind us that (fqy)x(lng) = speed.
So . . . F x W = 343 m/s
Divide each side by F :
W = (343 m/s) / F
W = (343 m/s) / (240 / s)
W = (343/240) m
<em>W = 1.429 meters</em>
You could add them on a number line or count on your fingers.