Which term best describes the set of all possible output values for a function

The cash price of a television is $580.the hire-purchase price of the television is $865.the hire-purchase price is an initial deposit of n% of the cash price and 6 equal monthly payments of $120.find the value of n.

If you could answer these your a life saver

F(x) = 1/x g(x)=x-4 can you evaluate (g*f)(0) ? why or why not?