1.已知抛物线y=x2-4x+3与x轴相交于点A,B(点A在点B左侧),顶点为M.平移该抛物线,使点M平移后的对应点M'落在x轴上,点B平移后的对应点B'落在y轴上,则平移后的抛物线解析式为( )
| A. | y=x2+2x+1 | B. | y=x2+2x-1 | C. | y=x2-2x+1 | D. | y=x2-2x-1 |
19.若点A(-1,y1),B(1,y2),C(3,y3)在反比例函数y=-$\frac{3}{x}$的图象上,则y1,y2,y3的大小关系是( )
| A. | y1<y2<y3 | B. | y2<y3<y1 | C. | y3<y2<y1 | D. | y2<y1<y3 |
18.方程组$\left\{\begin{array}{l}y=2x\\ 3x+y=15\end{array}\right.$的解是( )
| A. | $\left\{\begin{array}{l}x=2\\ y=3\end{array}\right.$ | B. | $\left\{\begin{array}{l}x=4\\ y=3\end{array}\right.$ | C. | $\left\{\begin{array}{l}x=4\\ y=8\end{array}\right.$ | D. | $\left\{\begin{array}{l}x=3\\ y=6\end{array}\right.$ |
17.计算$\frac{a}{a+1}+\frac{1}{a+1}$的结果为( )
| A. | 1 | B. | a | C. | a+1 | D. | $\frac{1}{a+1}$ |
15.据《天津日报》报道,天津市社会保障制度更加成熟完善,截止2017年4月末,累计发放社会保障卡12630000张.将12630000用科学记数法表示为( )
0 296062 296070 296076 296080 296086 296088 296092 296098 296100 296106 296112 296116 296118 296122 296128 296130 296136 296140 296142 296146 296148 296152 296154 296156 296157 296158 296160 296161 296162 296164 296166 296170 296172 296176 296178 296182 296188 296190 296196 296200 296202 296206 296212 296218 296220 296226 296230 296232 296238 296242 296248 296256 366461
| A. | 0.1263×108 | B. | 1.263×107 | C. | 12.63×106 | D. | 126.3×105 |