Choose the answer based on the most efficient method as presented in the lesson. if the first step in the solution of the equation -9 + x = 5x - 7 is "subtract x," then what should the next step be? subtract 5x add 7 add 9

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%