differentiation of explicit function vs implicit function

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I have the following implicit function: $xy=5$.

I want to get $y'$ or $\frac{dy}{dx}$.

In this case, implicit differentiation gives me $\frac{dy}{dx}=\frac{-y}{x}$.

I am curious why explicit differentiation cannot generate the same answer.

That is, $y=\frac{5}{x}$. And then $y'=\frac{dy}{dx} = \frac{-5}{x^2}$.

Any mistake or misunderstanding I have here?