Q: Let be a linear transformation, and let be a subspace of . Prove that the set is a subspace of . What is if ?

A: I dont have much, so I will show my train of thought...

First, I want to show is nonempty. I can do this by simply notingisa subspace; therefore, is nonempty. I don't know if I am reading the set correctly. Do I wan't to show the range of is nonempty?

I am confused by what represents.

Does it mean:

???

Thanks