Write a real-world problem that can be solved using the equation 9+4x=21−2x.

Pls! does anybody know a shortcut for answering these types of questions in the future?

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%

Which of the following is the graph of y= square root -x-3