问题
解答题
(1)计算
(2)已知实数a满足a2+2a-8=0,求
|
答案
(1)
-1
+12
+(8
-1)0=3
-1-22
+12
=-
;2
(2)
-1 a+1
×a+3 a2-1 a2-2a+1 a2+4a+3
=
-1 a+1
×a+3 (a-1)(a+1) (a-1)2 (a+1)(a+3)
=
-1 a+1
=a-1 (a+1)2
,2 (a+1)2
由已知,实数a满足a2+2a-8=0,故(a+1)2=9,
∴原式=
(9分).2 9