Which of the equations are true identities? a. (3x-2y)(2y-3x)=9x^2-4y^2 b. (2k+5r)(2k-5r)=4k^2-25r^2

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

Having a hard time understanding this question (see attachment).

Acompany made a profit of 75000 over a period of 6 years on an initial investment of 15000 what is the annual roi