Plz help due tomorrow

If the speed of an electromagnetic wave is 100,000 cm/s and its wavelength is 100 cm, what is its frequency? a) 100,000 cycles per second (hz) b) 1 × 10-3 cycles per second (hz) c) 10,000,000 cycles per second (hz) d) 1,000 cycles per second (hz)

If (x-2) 2= 49, then x could be a. -9 b. -7 c.- 2 d. 5 e.9

If value of cos330° is √3/2 then find tan165°.