(1)计算:(?1)2020×(12)?2+(sin98°?π2)0+|3?2sin60°|.(2)先化简,再求值:3x?3?18x2?9,其中x=

2025-01-01 10:54:29
推荐回答(1个)
回答1:

(1)原式=1×4+1+|

3
-2×
3
2
|
=4+1+|
3
-
3
|,
=4+1+0,
=5;

(2)原式=
3(x+3)?18
(x+3)(x?3)

=
3x+9?18
(x+3)(x?3)

=
3x?9
(x+3)(x?3)

=
3
x+3

当x=
10
-3时,原式=
3
10
?3+3
=
3