Which of these is the characteristic equation for an=6an−1−8an−2a_n = 6a_{n-1} - 8a_{n-2}an=6an−1−8an−2?
r2+6r−8=0r^2 + 6r - 8 = 0r2+6r−8=0
r2−6r+8=0r^2 - 6r + 8 = 0r2−6r+8=0
r2−6r−8=0r^2 - 6r - 8 = 0r2−6r−8=0
r2+6r+8=0r^2 + 6r + 8 = 0r2+6r+8=0