如图,△ABC是等边三角形,点D为 AC边上一点,以BD为边作等边△BDE, 连接CE.若CD=1,CE=3,则BC=_____.
-2.6的相反数是_____,倒数是_____,绝对值是______;
-的相反数是______,倒数是_______;
_____÷(-2)=0,依据法则是__________;
(-63)÷7=_____,依据法则是__________;
(-42)÷(-6)=_____,依据法则是__________;