(1)解方程:x2+22x-6=0(2)先化简,再求值:2xx+1-2x+6x2?1÷x+3x2?2x+1,其中x2-9=0

2024-07-16 13:37:07
推荐回答(1个)
回答1:

(1)∵△=(2

2
2-4×1×(-6)=4
2

∴x=
?2
2
±4
2
2
,即x1=-3
2
,x2=
2


(2)原式=
2x
x+1
-
2(x+3)
(x+1)(x?1)
÷
x+3
(x?1)2

=
2x(x?1)?2(x+3)
(x+1)(x?1)
?
(x?1)2
x+3

=
2(x?3)
x?1
?
(x?1)