The lcm of a prime nunber and a composite number is a multiple of the prime number. is this always, sometimes or never?

(hurry! ) which expression is equivalent to the following complex fraction?

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.

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?