2.体育委员统计了全班同学60秒跳绳的次数,并列出下面的频数分布表:
从表中可知,组距和组数分别是( )
| 次数(x) | 60≤x<80 | 80≤x<100 | 100≤x<120 | 120≤x<140 | 140≤x<160 | 160≤x<180 | 180≤x<200 |
| 频数(人数) | 2 | 4 | 21 | 13 | 8 | 4 | 1 |
| A. | 组距8,组数20 | B. | 组距20,组数7 | C. | 组距7,组数20 | D. | 组距40,组数7 |
1.
图中两条直线l1和l2的交点坐标可以看作下列方程组中( )的解.
| A. | $\left\{\begin{array}{l}y=2x+1\\ y=x+2\end{array}\right.$ | B. | $\left\{\begin{array}{l}y=3x+1\\ y=x-5\end{array}\right.$ | C. | $\left\{\begin{array}{l}y=-2x+1\\ y=x-1\end{array}\right.$ | D. | $\left\{\begin{array}{l}y=-x+3\\ y=3x-5\end{array}\right.$ |
16.若函数y=$\frac{k}{\sqrt{2}x}$(k>0)的图象上有三点A1(x1,y1),A2(x2,y2),A3(x3,y3),已知x1<x2<0<x3,则下列正确的是( )
| A. | y1<y2<y3 | B. | y3<y2<y1 | C. | y2<y1<y3 | D. | y3<y1<y2 |
15.代数式$\frac{2}{x}$,$\frac{a}{3}$,$\frac{m+n}{m-n}$,$\frac{{x}^{2}}{x}$、$\frac{x}{π-1}$中,分式有( )
0 308708 308716 308722 308726 308732 308734 308738 308744 308746 308752 308758 308762 308764 308768 308774 308776 308782 308786 308788 308792 308794 308798 308800 308802 308803 308804 308806 308807 308808 308810 308812 308816 308818 308822 308824 308828 308834 308836 308842 308846 308848 308852 308858 308864 308866 308872 308876 308878 308884 308888 308894 308902 366461
| A. | 4个 | B. | 3个 | C. | 2个 | D. | 1个 |