问题
解答题
先化简,再求值:
|
答案
-x x+1
•x+3 x+1 x2-2x+1 x2+4x+3
=
-x x+1
•x+3 x+1 (x-1)2 (x+1)(x+3)
=
-x x+1 (x-1)2 (x+1)2
=x(x+1)-(x-1)2 (x+1)2
=
,3x-1 (x+1)2
当x=1时,原式=
=3-1 (1+1)2
.1 2
先化简,再求值:
|
-x x+1
•x+3 x+1 x2-2x+1 x2+4x+3
=
-x x+1
•x+3 x+1 (x-1)2 (x+1)(x+3)
=
-x x+1 (x-1)2 (x+1)2
=x(x+1)-(x-1)2 (x+1)2
=
,3x-1 (x+1)2
当x=1时,原式=
=3-1 (1+1)2
.1 2