Which characteristic equation corresponds to an=2an−1+8an−3a_n = 2a_{n-1} + 8a_{n-3}an=2an−1+8an−3?
r3−2r2−8=0r^3 - 2r^2 - 8 = 0r3−2r2−8=0
r2−2r−8=0r^2 - 2r - 8 = 0r2−2r−8=0
r3−2r−8=0r^3 - 2r - 8 = 0r3−2r−8=0
r3+2r2+8=0r^3 + 2r^2 + 8 = 0r3+2r2+8=0