Simplify the expression: 9(x-4)

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.

Subscriptions to a popular fashion magazine have gone down by a consistent percentage each year and can be modeled by the function y = 42,000(0.96)t. what does the value 42,000 represent in the function?

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?