I have some troubles with the next exercise. I'm preparing for an exam and I have been trying to solve this with no success.
Justify that the system of equations $$ uv - 3x + 2y = 0$$ $$u^4 - v^4 = x^2 - y^2$$ defines implicitly to $u$ and $v$ as functions of $(x,y)$ in $(1,1,1,1)$ and find the equations of tangent planes to the graphs of functions $u(x,y)$ and $v(x,y)$ in $(1,1)$.
I have solved this type of exercises with an only equation but I feel a bit lost with more ones. Any advice/help to solve this?