14.在学习了《∮5.1投影》之后,小明拿着一个矩形木框操场上做投影实验,阳光下这个矩形木框在地面上的投影不可能是( )
| A. | 矩形 | B. | 梯形 | C. | 正方形 | D. | 平行四边形 |
9.若点A(-2,0)、B(-1,a)、C(0,4)在同一条直线上,则a的值是( )
0 286789 286797 286803 286807 286813 286815 286819 286825 286827 286833 286839 286843 286845 286849 286855 286857 286863 286867 286869 286873 286875 286879 286881 286883 286884 286885 286887 286888 286889 286891 286893 286897 286899 286903 286905 286909 286915 286917 286923 286927 286929 286933 286939 286945 286947 286953 286957 286959 286965 286969 286975 286983 366461
| A. | 2 | B. | 1 | C. | -2 | D. | 4 |