Let's see I have the following equation
$$ x=1 $$
I take the derivate of both sides with respect to $x$:
$$ \frac{\partial }{\partial x} x = \frac{\partial }{\partial x}1 $$
Therefore, $1=0$. Clearly, that is not the right approach.
So what is the right way to think of $x=1$. What kind of object is it?