解方程和不等式组:
(1) x 2 x - 5 + 5 5 - 2 x = 1
(2) 5 x - 10 ⩽ 0 x + 3 > - 2 x .
-2 +(-2) -(-1)
-10÷5×6
-2+5
计算:(1).(2)5.6+(-0.9)+4.4+(-8.1)(3)(4).(5) (6)
(本题6分)+()-1-sin45°+|-2013|