I am an unconditional admirer of WolframAlpha and for this reason I want to let the people of this error (or is it really the fault of mine?). If I'm not mistaken, I would be very happy to contribute, communicating this default calculation, to this extraordinary and beneficial website.
I was watching something on the cubic curve $$y^2=x^3+7x+9$$ More precisely I was interested in integer points $(x, y)$ with both coordinates being prime numbers. I thought having in hand the point $ (5,\pm 13) $ but, consulting WolphramAlpha, his answer gives only the two points $(-1,\pm 1)$ and $(0,\pm 3)$
Maybe I need to rest a bit ...
I believe wolfram is right, $$(-13)^3+7(-13)+9=-2279 \neq 5^2$$ and similarly $$13^3+7(13)+9=2297 \neq 5^2$$ and $\sqrt{2297} \notin \mathbb Z$
EDIT: Switching $x$ and $y$ it seems that $5^3+7(5)+9=13^2$, so yes you're correct!