More directly than the other comments: No you can’t solve for x and y here and yes your intuition is wrong.

These are functions. I don’t know your level of knowledge in math or programming and what that would mean to you. Here’s an example.

double(x) -> x*2

So, double(3) = 6. You can’t solve for x because x doesn't have a value. It’s a placeholder for whatever you put in.

These combinators are functions that take other functions and return them unmodified. “Unmodified” is a little misleading because it can do things like drop inputs.