(1)化简 x − 1 x ÷ ( x − 1 x ) .
(2)解方程: 2 x 2 x − 1 + 5 1 − 2 x = 3 .
-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|