On a math test, 4 out of 20 students received an a. two students are randomly selected without replacement, and the first student has an a. what is the probability of the second student having an a?

Find the sum of 4x^{2} -4+6 and -7^{2} +3x+1

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)

Ineed to know the answer to this algebra question.