What is the greatest common factor of 4k, 18k^4, and 12?

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)

Solve the equation by completing the square. x^2+2x=17

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)