your first zero is -5 (you get this from looking at x+5) then you can just punch it into your graphing calculator and it'll give you the two other zeros: -2/5 and 0
the reason you get these two zeros is because -2x^3-5x^2 turns into 2/5x^3 -x^2
the x^2 is of multiplicity 2 so it'll 'bounce' off the graph at 0 like in the photo I've included