6.方程x-3=-6的解是( )
| A. | x=2 | B. | x=-2 | C. | x=3 | D. | x=-3 |
4.下列各数:3.414,-$\frac{22}{7}$,$\sqrt{8}$,π,4.$\stackrel{•}{2}$$\stackrel{•}{1}$$\stackrel{•}{7}$,0.1010010001…,其中无理数有( )
| A. | 1个 | B. | 2个 | C. | 3个 | D. | 4个 |
3.已知a<b,下列不等式变形中正确的是( )
| A. | a-2>b-2 | B. | $\frac{a}{3}$>$\frac{b}{3}$ | C. | 3a+1>3b+1 | D. | -2a>-2b |
1.下列事件中最适合使用全面调查方式收集数据的是( )
0 284640 284648 284654 284658 284664 284666 284670 284676 284678 284684 284690 284694 284696 284700 284706 284708 284714 284718 284720 284724 284726 284730 284732 284734 284735 284736 284738 284739 284740 284742 284744 284748 284750 284754 284756 284760 284766 284768 284774 284778 284780 284784 284790 284796 284798 284804 284808 284810 284816 284820 284826 284834 366461
| A. | 了解某班同学的身高情况 | B. | 了解全国每天丢弃的废旧电池数 | ||
| C. | 了解一批炮弹的杀伤半径 | D. | 了解我国农民的年人均收入情况 |