先化简,再求值: ( x 2 x − 2 + 4 2 − x ) ÷ x 2 + 4 x + 4 x .其中 x 是0,1,2这三个数中合适的数.
(11·十堰)计算:-2-1+︱-1︱.
(11·丹东)(本题8分)计算:
计算: (1) (2)
(8分)计算: