(1)原式=?
+3?(1 4
)?1+1?
3
?1(4分)
3
=?
+1 4
+1?
3
?1(6分)
3
=?
(8分);1 4
(2)原式=
÷x+x+1 x+1
-1?x2?3x2
1?x2
(2分)1 x?1
=
÷2x+1 x+1
-(1+2x)(1?2x) (x+1)(1?x)
1 x?1
×2x+1 x+1
-(1+x)(1?x) (2x+1)(1?2x)
1 x?1
=
-1?x 1?2x
1 x?1
=
.(6分)?x2+4x?2 (1?2x)(x?1)
取x