2N2O(g) → 2N2(g) + O2(g)

d[N2O]/dt = -5.8×10-4 M/s at a particular temperature and set of concentrations.

What are d[O2]/dt and d[N2]/dt?
d[O2]/dt =
d[N2]/dt =

What is the rate of the reaction?

my answer for the first one im getting -.00016 and the second one 2.9e-4

and i don't understand how to do the last part, do i add up all the values together?