问题
解答题
先化简,再求值:(
|
答案
原式=[
-a-2 a(a+2)
]•a-1 (a+2)2 a+2 a-4
=
•a2-4-a2+a a(a+2)2 a+2 a-4
=
•a-4 a(a+2)2 a+2 a-4
=
.1 a(a+2)
当a=
-1时,原式=2
=1.1 (
-1)(2
-1+2)2
先化简,再求值:(
|
原式=[
-a-2 a(a+2)
]•a-1 (a+2)2 a+2 a-4
=
•a2-4-a2+a a(a+2)2 a+2 a-4
=
•a-4 a(a+2)2 a+2 a-4
=
.1 a(a+2)
当a=
-1时,原式=2
=1.1 (
-1)(2
-1+2)2