1.某小区在规划设计时,准备在两幢楼房之间,设置一块周长为120米的长方形绿地,并且长比宽多10米.设绿地的宽为x米,根据题意,下面列出的方程正确的是( )
| A. | 2(x-10)=120 | B. | 2[x+(x-10)]=120 | C. | 2(x+10)=120 | D. | 2[x+(x+10)]=120 |
20.下列不等式一定成立的是( )
| A. | x+2<x+3 | B. | 5a>4a | C. | -a>-2a | D. | $\frac{4}{a}>\frac{2}{a}$ |
19.若 $\left\{\begin{array}{l}x=2\\ y=1\end{array}\right.$是方程组$\left\{\begin{array}{l}ax-3y=1\\ x+by=5\end{array}\right.$的解,则a、b值为( )
| A. | $\left\{\begin{array}{l}a=2\\ b=3.\end{array}\right.$ | B. | $\left\{\begin{array}{l}a=-2\\ b=3.\end{array}\right.$ | C. | $\left\{\begin{array}{l}a=2\\ b=-3.\end{array}\right.$ | D. | $\left\{\begin{array}{l}a=-2\\ b=-3.\end{array}\right.$ |
18.方程1-3x=0的解是( )
| A. | x=-$\frac{1}{3}$ | B. | x=$\frac{1}{3}$ | C. | x=-3 | D. | x=3 |
17.
如图,在平面直角坐标系中,直线l1:y=x+3与直线l2:y=mx+n交于点A(-1,b),则关于x、y的方程组$\left\{\begin{array}{l}y=x+3\\ y=mx+n\end{array}\right.$的解为( )
| A. | $\left\{\begin{array}{l}x=2\\ y=1\end{array}\right.$ | B. | $\left\{\begin{array}{l}x=2\\ y=-1\end{array}\right.$ | C. | $\left\{\begin{array}{l}x=-1\\ y=2\end{array}\right.$ | D. | $\left\{\begin{array}{l}x=-1\\ y=-2\end{array}\right.$ |
16.
如图,直线a∥b,AC⊥AB,AC交直线b于点C,∠1=60°,则∠2的度数是( )
| A. | 50° | B. | 45° | C. | 35° | D. | 30° |
15.
如图,四边形ABCD是⊙O的内接四边形,AC是⊙O直径,点P在AC的延长线上,PD是⊙O的切线,延长BC交PD于点E.则下列说法不正确的是( )
| A. | ∠ADC=∠PDO | B. | ∠DCE=∠DAB | C. | ∠1=∠B | D. | ∠PCD=∠PDA |
13.某小组5名同学一周内参加家务劳动的时间如表所示,关于劳动时间这组数据,下列说法正确的是( )
| 劳动时间(小时) | 1 | 2 | 3 | 4 |
| 人数 | 1 | 1 | 2 | 1 |
| A. | 众数是2,平均数是 2.6 | B. | 中位数是3,平均数是2 | ||
| C. | 众数和中位数都是3 | D. | 众数是2,中位数是3 |
12.下列各数中最小的数是( )
0 285849 285857 285863 285867 285873 285875 285879 285885 285887 285893 285899 285903 285905 285909 285915 285917 285923 285927 285929 285933 285935 285939 285941 285943 285944 285945 285947 285948 285949 285951 285953 285957 285959 285963 285965 285969 285975 285977 285983 285987 285989 285993 285999 286005 286007 286013 286017 286019 286025 286029 286035 286043 366461
| A. | $-\frac{π}{2}$ | B. | -$\sqrt{2}$ | C. | 0 | D. | 1 |