先化简,再求值:(3x+4x2?1-2x?1)÷x+2x2?2x+1,其中x是方程(x+2)2-10(x+2)+25=0的解

2025-12-17 10:27:37
推荐回答(1个)
回答1:

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