What are the possible rational zeros of f(x) = x4 + 2x3 − 3x2 − 4x − 12?
a. ± 1, ± 2, ± 3, ± 4, ± 5, ± 6, ± 7, ± 8, ± 9, ± 10, ± 11, ± 12
b. 1, 2, 3, 4, 6, 12
c. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
d. ± 1, ± 2, ± 3, ± 4, ± 6, ± 12

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%