Help asap plsplspls !!

What is f(3) for the quadratic functionf(x)=2x2 + x – 12? f -3g 3h 6i. 9

The sum of two numbers is 86, and their difference is 20. find the two numbers

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%