9.下列各数:-0.1,$\frac{2}{5}$,3.14,-8,0,100,-$\frac{1}{3}$.其中负数有( )
| A. | 1个 | B. | 2个 | C. | 3个 | D. | 4个 |
8.方程x2-121=0的根是( )
| A. | 11 | B. | -11 | C. | 11或-11 | D. | 14或-14 |
7.下列运算正确的是( )
| A. | -22=4 | B. | (-2)3=-6 | C. | ${(-\frac{1}{2})^3}=-\frac{1}{8}$ | D. | ${({-2\frac{1}{3}})^3}=-8\frac{1}{27}$ |
5.因式分解(x-4)2-9的结果是( )
| A. | (x-1)(x+1) | B. | (x-1)(x-5) | C. | (x-13)(x+5) | D. | (x-1)(x-7) |
4.以下可以用作证明命题“若a>b,则|a|>|b|”是假命题的反例的是( )
| A. | a=3,b=2 | B. | a=0,b=-1 | C. | a=2,b=-1 | D. | a=5,b=0 |
3.下列语句属于命题的是( )
0 288437 288445 288451 288455 288461 288463 288467 288473 288475 288481 288487 288491 288493 288497 288503 288505 288511 288515 288517 288521 288523 288527 288529 288531 288532 288533 288535 288536 288537 288539 288541 288545 288547 288551 288553 288557 288563 288565 288571 288575 288577 288581 288587 288593 288595 288601 288605 288607 288613 288617 288623 288631 366461
| A. | 作直线AB的平行线 | B. | 在线段AB上任取一点C | ||
| C. | 等角的余角相等 | D. | 同位角都相等吗? |