If a recurrence an=c1an−1+c2an−2a_n = c_1 a_{n-1} + c_2 a_{n-2}an=c1an−1+c2an−2 has roots r1=1r_1=1r1=1 and r2=2r_2=2r2=2, what is the characteristic equation?
r2−3r+2=0r^2 - 3r + 2 = 0r2−3r+2=0
r2+3r+2=0r^2 + 3r + 2 = 0r2+3r+2=0
r2−2r+1=0r^2 - 2r + 1 = 0r2−2r+1=0
r2+3r−2=0r^2 + 3r - 2 = 0r2+3r−2=0