A:团结就是力量
B:合作的作用
C:竞争的作用
D:合作与竞争的关系
定义新运算:对于任意实数m、n都有m☆n=m2n+n,等式右边是常用的加法、减法、乘法及乘方运算.例如:﹣3☆2=(﹣3)2×2+2=20.根据以上知识解决问题:若2☆a的值小于0,请判断方程:2x2﹣bx+a=0的根的情况.
长江在我国众多的河流中居首位的是( )①流域面积 ②流程长度 ③含沙量 ④年径流量 ⑤结冰期 ⑥水能蕴藏量
I wish I……
Flags have existed for over 3,000 years. The earliest flags were wooden or metal poles with a carving. About 2,000 years ago pieces of fabric were added to some poles for decoration. Over the next 500 years the free-flying part of the flag became more important.