Rewrite the expression in the form k x y^n

When turned about its axis of rotation, which shape could have created this three-dimensional object?

Asocial networking site currently has 400,000 active members, and that figure is predicted to increase by 32% each year. the following expression represents the number of active members on the site after t years.

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much