2.
二次函数y=ax2+bx+c(a≠0)的图象如图所示,下列说法:
①2a+b=0;
②当-1≤x≤3时,y<0;
③若(x1,y1)、(x2,y2)在函数图象上,当x1<x2时,y1<y2
④9a+3b+c=0
其中正确的是( )
①2a+b=0;
②当-1≤x≤3时,y<0;
③若(x1,y1)、(x2,y2)在函数图象上,当x1<x2时,y1<y2
④9a+3b+c=0
其中正确的是( )
| A. | ①②④ | B. | ①②③ | C. | ①④ | D. | ③④ |
14.16的算术平方根是( )
0 294839 294847 294853 294857 294863 294865 294869 294875 294877 294883 294889 294893 294895 294899 294905 294907 294913 294917 294919 294923 294925 294929 294931 294933 294934 294935 294937 294938 294939 294941 294943 294947 294949 294953 294955 294959 294965 294967 294973 294977 294979 294983 294989 294995 294997 295003 295007 295009 295015 295019 295025 295033 366461
| A. | ±4 | B. | ±2 | C. | 4 | D. | -4 |