What is 2(-9x-4y-7) simplified

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%

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.