原式=(
-3x+4 (x+1)(x?1)
)×2 x?1
=(x?1)2
x+2
-(3x+4)(x?1) (x+1)(x+2)
=2(x?1) x+2
-(3x+4)(x?1) (x+1)(x+2)
=2(x?1)(x+1) (x+1)(x+2)
=(3x+4)(x?1)?2(x?1)(x+1) (x+1)(x+2)
,x?1 x+1
∵x是方程(x+2)2-10(x+2)+25=0的解,
∴x=3,
∴当x=3时,原式=
=3?1 3+1
.1 2