填空:x2+10x+ =(x+ )2.
如果n是正整数,且a=―1,那么―a 2n+1=_________.
若.
化简①②.
-的相反数是__________, -的绝对值是_________,-的倒数是_________.
把规定了_________, _________, __________的直线叫数轴.