What is the slope of the line that passes through the points (-4, 0) and (2, 0)? Write you answer in simplist form

Ineed if you could explain and give me the answer you! this needs done

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%

Percent increase and decrease. original number: 45 new number: 18