Determine whether the systems with the following characteristic equations are stable, marginally stable or unstable. If they are unstable, how many poles in the RHP do they have?
a) s³+s+10 = 0
b) s⁴+4s³+9s²+10s = 0
c) s⁵ +2s⁴ + s +2 =0
d) s⁵ +s⁴ + 8s³ + 8s² +2 =0