19.将抛物线y=-$\frac{1}{3}$(x-2)2向右平移1个单位,再向下平移2个单位后,得到的抛物线解析式为( )
| A. | y=-$\frac{1}{3}$(x-1)2+2 | B. | y=-$\frac{1}{3}$(x-1)2-2 | C. | y=-$\frac{1}{3}$(x-3)2+2 | D. | y=-$\frac{1}{3}$(x-3)2-2 |
18.已知x2-2x-1=0,则2x2-4x的值为( )
| A. | -2 | B. | 2 | C. | -2或6 | D. | 2或6 |
17.已知双曲线y=$\frac{k}{x}$上有一点P(2,-3),则点A(6,1)、B(-2,3)、C($\frac{1}{2}$,-12)、D(-7,1)中,在该双曲线上的还有( )
| A. | 点A、B | B. | 点A、C | C. | 点B、C | D. | 点B、D |
16.
如图,数轴上的点A表示的数为x,化简|x|+|1-x|的结果为( )
| A. | 1 | B. | 2x-1 | C. | 2x+1 | D. | 1-2x |
14.在下列调查中,宜采用全面调查的是( )
| A. | 了解某区中小学生视力情况 | B. | 了解七(2)班学生校服的尺码情况 | ||
| C. | 检测一批炮弹的使用寿命 | D. | 调查《1818黄金眼》栏目的收视率 |
13.二元一次方程组$\left\{\begin{array}{l}{2x+y=5}\\{x-y=1}\end{array}\right.$的解是( )
| A. | $\left\{\begin{array}{l}{x=3}\\{y=2}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x=1}\\{y=2}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x=4}\\{y=3}\end{array}\right.$ |
12.
如图所示,点E在AC的延长线上,下列条件中能判断AB∥CD的是( )
| A. | ∠1=∠2 | B. | ∠3=∠4 | C. | ∠D=∠DCE | D. | ∠D+∠ACD=180° |
11.下列运算正确的是( )
| A. | a2•a6=a12 | B. | a8÷a4=a4 | C. | (-3a2b3)3=-3a6b9 | D. | (a+b)2=a2+b2 |
10.下面式子从左边到右边的变形为因式分解的是( )
0 297852 297860 297866 297870 297876 297878 297882 297888 297890 297896 297902 297906 297908 297912 297918 297920 297926 297930 297932 297936 297938 297942 297944 297946 297947 297948 297950 297951 297952 297954 297956 297960 297962 297966 297968 297972 297978 297980 297986 297990 297992 297996 298002 298008 298010 298016 298020 298022 298028 298032 298038 298046 366461
| A. | x2-x-2=x(x-1)-2 | B. | (a+b)(a-b)=a2-b2 | C. | x2-1=(x+1)(x-1) | D. | xy-y3=xy(1-$\frac{{y}^{2}}{x}$) |