5.下列不等式中,不含有x=-1这个解的是( )
| A. | 2x+1≤-3 | B. | 2x-1≥-3 | C. | -2x+1≥3 | D. | -2x-1≤3 |
4.用相同的钱,小聪买的笔蕊数量是小明买笔记本数量的2倍,每本笔记本比每支笔蕊多1元.设每支笔蕊x元,小明依题意列得两个方程,①2x=x+1②$\frac{1}{x}$=$\frac{2}{x+1}$,下列判断正确的是( )
| A. | 只有①是对的 | B. | 只有②是对的 | C. | ①②都是对的 | D. | ①②都是错的 |
3.下列各项中,不是不等式x≤2解的是( )
| A. | 0 | B. | $\sqrt{2}$ | C. | 2 | D. | $\sqrt{5}$ |
2.下列四个数中,无理数是( )
| A. | π | B. | $\frac{1}{3}$ | C. | 0 | D. | $\sqrt{4}$ |
1.$-\frac{1}{4}$的绝对值是( )
0 284605 284613 284619 284623 284629 284631 284635 284641 284643 284649 284655 284659 284661 284665 284671 284673 284679 284683 284685 284689 284691 284695 284697 284699 284700 284701 284703 284704 284705 284707 284709 284713 284715 284719 284721 284725 284731 284733 284739 284743 284745 284749 284755 284761 284763 284769 284773 284775 284781 284785 284791 284799 366461
| A. | -4 | B. | $\frac{1}{4}$ | C. | 4 | D. | 0.4 |