Let x = wavelength and y = frequency. the equation that models the inverse relation is

y = (3 × 10^8 m/s)/x

Step-by-step explanation:

Speed of a wave is given by the product of wavelength and frequency.

Thus; speed = frequency × wavelength

If  x = wavelength and y = frequency then speed will be;

speed = yx

Thus to get wavelength, y;

y = speed/x , but speed is 3 × 10^8 m/s

Thus;

y = (3 × 10^8 m/s)/x

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)

1/5^2 = 7.56/45