(本题满分8分,每小题4分)(1)计算: (2)解方程组:
(泸州)计算:.
(泸州)化简:.
(凉山州)计算:.
(凉山州)先化简:,然后从的范围内选取一个合适的整数作为x的值代入求值.
(资阳)先化简,再求值:,其中x满足.