计算:(+1)(2-)
(本小题满分8分)解不等式组: (1) (2)
(本小题满分8分)解方程组: (1) (2)
(本小题满分4分)化简求值:,其中.
(本小题满分3分)计算:.
(本小题满分3分)计算:()(精确到0.1).