解不等式组: 2 x − 1 < x + 5 ① x + 1 3 < x − 1 ② .
计算题 (每小题3分,共6分)(1) (2)(3)
计算:(1)(2)
.(本题8分)计算:
(本题15分)计算:(1)(2)(3)
计算: