Please I need help ASAP

Which function has the same domain as y=2x

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%

Consider the sequence below. 3 , 1 , 1/3 , 1/9 , select the explicit function which defines the sequence.