(1)计算:2cos60°?(2009?π)0+9(2)先化简、再求值:a?32a?4÷(5a?2?a?2),其中a=3?3

2025-05-26 08:32:46
推荐回答(1个)
回答1:

(1)原式=2×

1
2
-1+3                 (3分)
=3;(4分)
(2)原式=
a?3
2(a?2)
÷[
5?(a+2)(a?2)
(a?2)
]

=
a?3
2(a?2)
?
a?2
9?a2
(6分)
=
a?3
2(a?2)
?
a?2
(3+a)(3?a)

=?
1
2(a+3)
.                     (8分)
a=
3
?3
时,
原式=?
1
2(
3
?3+3)
=?
3
6
.               (9分)