(1996x)的平方-1995×1997x-1=0
(1996x)²-(1996-1)(1996+1)x-1=0
(1996x)²-(1996²-1)x-1=0
(1996x)²-1996²x+x-1=0
1996²x(x-1)+x-1=0
(x-1)(1996²x-1)=0
∴X1=1
X2=1/1996²=M
x²+1996x-1996=0
(x-1)(x+1996)=0
∴X3=1
X4=-1996=N
∴M=1/1996²
N=-1996