f(x)=x^(10)e^(−13x)

The derivative is f(x)=(10x^(9)−13x^(10)) * e^ (−13x)

The derivative is right because its given, I don't understand how solve for x = 0 correctly to find the critical points.. can someone direct me?

I would have thought x = 0 and sqrt(10/13) but apparently i not correct.