I just don't get this problem, I feel I'm missing something obvious.

Find if

and

Poor attempt of solution:

I try to obtain an expression for x as a function of u and v, but I can't seem to be able to get anything from that system of equations.

From 1) I get , but from 2)

If I replace into 1)

I don't think I'm getting something from that

If then

Another thought from there:

then,

, but

and I think I'm running in circles here.