indicate stability or instability of each critical point in dx/dt=x^3-5x?

Question

above says it all. I think I got it but i'd like to make sure

Answer 1

dx/dt = 0 <=> x (x^2 - 5) = 0 <=> x = 0 or ±√5.

Sign diagram for dx/dt:
. . . . -√5 . . . . 0 . . . . √5 . . . . .
-ve . . . . . +ve . . . -ve . . . +ve
<-- . . . . . --> . . . . <-- . . . -->
Thus x moves away from the points at ±√5 and towards the critical point at x=0. So the ciritical point at x=0 is stable but the ones at ±√5 are unstable.