5x + 4x is equivalent to 9x. Substitute values for x to show that this is true. please help!!
worth 30 points

(urgent ) use pi 3.14 to estimate the circumference of the circle to the nearest hundredth middle is 4in (urgent )

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%

A. what is the area of the base? use complete sentences to explain your reasoning. b. what is the volume of the prism? use complete sentences to explain your reasoning.