Kind of stuck ,
factor completely: 3a4y3 − 12a3y2 + 6a2y

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=