11.抛物线x2=-4y的焦点坐标为( )
| A. | (1,0) | B. | (0,1) | C. | (-1,0) | D. | (0,-1) |
10.已知直线l过不同的两点A(5,-3),B(5,y),则l的斜率为( )
| A. | 0 | B. | 5 | C. | 不存在 | D. | 与y的取值有关 |
6.设直线l1:2x-my-1=0,l2:(m-1)x-y+1=0.若l1∥l2,则m的值为( )
0 252740 252748 252754 252758 252764 252766 252770 252776 252778 252784 252790 252794 252796 252800 252806 252808 252814 252818 252820 252824 252826 252830 252832 252834 252835 252836 252838 252839 252840 252842 252844 252848 252850 252854 252856 252860 252866 252868 252874 252878 252880 252884 252890 252896 252898 252904 252908 252910 252916 252920 252926 252934 266669
| A. | 2 | B. | -1 | C. | 2或-1 | D. | 1或-2 |