What is the characteristic equation of an=3an−1−2an−2a_n = 3a_{n-1} - 2a_{n-2}an=3an−1−2an−2?
r2−3r+2=0r^2 - 3r + 2 = 0r2−3r+2=0
r2+3r−2=0r^2 + 3r - 2 = 0r2+3r−2=0
r2−3r−2=0r^2 - 3r - 2 = 0r2−3r−2=0
r2+3r+2=0r^2 + 3r + 2 = 0r2+3r+2=0