问题
解答题
计算求值 ①(3
②
③先化简,再求值:
|
答案
(1)原式=(12
+23
-63
)÷3
=83
÷3
=8;3
(2)原式=3
-2
-(1+3 2 2
)+1+2
-12
=
-1;3 2 2
(3)原式=
-3 x-3 18 (x-3)(x+3)
=3(x+3)-18 (x-3)(x+3)
=3(x-3) (x-3)(x+3)
=
,3 x+3
当x=
-3时,原式=10
=3
-3+310
.3 10 10