What is the probability of the youngest four members of a 15-member choir being randomly selected for a group of four singers?

How do you use the additive inverse to evaluate an expression that uses subtraction in a full sentence

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Atriangle with all sides of equal length is a/an triangle. a. right b. scalene c. equilateral d. isosceles