Which of the following recurrence relations is non-homogeneous?
an=2an−1−3an−2a_n = 2a_{n-1} - 3a_{n-2}an=2an−1−3an−2
an=an−1+an−2+5a_n = a_{n-1} + a_{n-2} + 5an=an−1+an−2+5
an=4an−1a_n = 4a_{n-1}an=4an−1
an=−an−1+2an−2a_n = -a_{n-1} + 2a_{n-2}an=−an−1+2an−2