What is the value of the length of a rectangle, if the perimeter is 5x + 12 and the width is x - 4?

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

I’m on question 7 it says a covered water tank is in the shape of a cylinder the tank has a 28 inch diameter and a height of 66 inches to the nearest square inch what is the surface area of the water tank

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.