X is usually representing time so years, days, etc
Answer:
D. Scientific notation is a way of writing large and small numbers
Wavelength= velocity/frequency
wavelength= (3.0 x 10^8m/s) / 7.5 x 10^12 Hz)
you can do the math
I am assuming u that 108 is 10^8 and the 1012 is 10^12
