What is the characteristic equation of an−4an−1+4an−2=0a_n - 4a_{n-1} + 4a_{n-2} = 0an−4an−1+4an−2=0?
r2−4r+4=0r^2 - 4r + 4 = 0r2−4r+4=0
r2+4r+4=0r^2 + 4r + 4 = 0r2+4r+4=0
r2−4=0r^2 - 4 = 0r2−4=0
r2+4=0r^2 + 4 = 0r2+4=0