Brenda and michael simplify the expression, as shown below.

brenda: -5x + (2+x) = -5 + x + 2 = -4x + 2

michael: -5x + (2 + x) = (-5x + 2) + x = -3 + x

who simplified the expression correctly?

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%