7.
如图,A的坐标是(0,4),点C是x轴上的一个动点,点B与点O在直线AC两侧,∠BAC=∠OAC,BC⊥AC,点B的坐标为(x,y),y与x的函数关系式为( )
| A. | y=8x | B. | y=$\frac{8}{x}$ | C. | y=$\frac{1}{16}{x}^{2}$ | D. | y=$\frac{16}{x}$ |
6.一个几何体从正面看、从左面看都是等腰三角形,从上面看是圆,那么它可能是( )
| A. | 三棱锥 | B. | 三棱柱 | C. | 圆柱 | D. | 圆锥 |
3.已知m-n=100,x+y=-1,则代数式(n+x)-(m-y)的值是( )
0 286806 286814 286820 286824 286830 286832 286836 286842 286844 286850 286856 286860 286862 286866 286872 286874 286880 286884 286886 286890 286892 286896 286898 286900 286901 286902 286904 286905 286906 286908 286910 286914 286916 286920 286922 286926 286932 286934 286940 286944 286946 286950 286956 286962 286964 286970 286974 286976 286982 286986 286992 287000 366461
| A. | -99 | B. | -101 | C. | 99 | D. | 101 |