12.若线段AB的端点坐标分别为A(-2,3),B(0,5),将它向下平移5个单位,则其端点坐标变为( )
| A. | A′(3,3),B′(0,0) | B. | A′(-2,-2),B′(0,0) | C. | A′(3,3),B′(5,5) | D. | A′(3,3),B′(-5,5) |
11.下列数学表达式中,①-8<0;②4a+3b>0;③a=3;④a+2>b+3,不等式有( )
| A. | 1个 | B. | 2个 | C. | 3个 | D. | 4个 |
5.给出的下列各数:-1,0,0.5,$\sqrt{7}$,$\root{3}{8}$,π,其中是无理数的个数有( )
0 282544 282552 282558 282562 282568 282570 282574 282580 282582 282588 282594 282598 282600 282604 282610 282612 282618 282622 282624 282628 282630 282634 282636 282638 282639 282640 282642 282643 282644 282646 282648 282652 282654 282658 282660 282664 282670 282672 282678 282682 282684 282688 282694 282700 282702 282708 282712 282714 282720 282724 282730 282738 366461
| A. | 0个 | B. | 2个 | C. | 3个 | D. | 6个 |