A:甲为4N,乙为8N
B:甲为4N,乙为4N
C:甲为8N,乙为8N
D:甲为4N,乙为0N
I don't know ______.
已知:4x2-1=Ax-1+Bx+1是一个恒等式,则A=____ ,B=____ .