Which of the following linear time invariant system is a purely recur

1.	Which of the following linear time invariant system is a purely recursive system?
A.	y(n) = $-\sum_{k=1}^{N} a_k y(n-k)+\sum_{k=0}^{M} b_k x(n-k)$
B.	y(n) = $\sum_{k=1}^{N} a_k y(n-k)+\sum_{k=0}^{M} b_k x(n-k)$
C.	y(n) = $-\sum_{k=1}^{N} a_k y(n-k)-\sum_{k=0}^{M} b_k x(n-k)$
D.	y(n) = $-\sum_{k=1}^{N} a_k y(n-k)+b_0x(n)$
Answer» E.

Discussion

1.	Which of the following linear time invariant system is a purely recursive system?
A.	y(n) = \(-\sum_{k=1}^{N} a_k y(n-k)+\sum_{k=0}^{M} b_k x(n-k)\)
B.	y(n) = \(\sum_{k=1}^{N} a_k y(n-k)+\sum_{k=0}^{M} b_k x(n-k)\)
C.	y(n) = \(-\sum_{k=1}^{N} a_k y(n-k)-\sum_{k=0}^{M} b_k x(n-k)\)
D.	y(n) = \(-\sum_{k=1}^{N} a_k y(n-k)+b_0x(n)\)
Answer» E.