I would like to know why there is a minus sign on the right-hand side of the Schrödinger's complex conjugate equation, whereas in the Schrödinger's equation there isn't. I know it is a simple question, but I don't know where this comes from.
$$
-\frac{\hbar^2 }{2m}\frac{\partial^2\psi}{\partial x^2} + V(x)\psi = i \hbar \frac{\partial \psi}{\partial t}
$$

$$
-\frac{\hbar^2 }{2m}\frac{\partial^2\psi^\*}{\partial x^2} + V(x)\psi^\* = -i \hbar \frac{\partial \psi^\*}{\partial t}
$$