Please help 20 points

Plot the points (0,6), (3,15.8), and (9.5,0) using the graphing tool, and find the function

What is the number 321,000,000 in scientific notation? also what is the number? ?

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%