9.不等式组$\left\{\begin{array}{l}{x+2≥0}\\{\frac{x}{2}-1<-\frac{1}{2}}\end{array}\right.$的解集在数轴上表示为( )
| A. | B. | C. | D. |
8.四边形ABCD的对角线AC、BD交于点O,有以下结论:①AB=BC;②∠DAB=90°;③BO=DO,AO=CO;④四边形ABCD是矩形;⑤四边形ABCD是菱形;⑥四边形ABCD是正方形.下列推论不正确的是( )
| A. | 由②③,得④ | B. | 由①③,得⑤ | C. | 由①②,得⑥ | D. | 由①④,得⑥ |
7.
如图,直线l1:y=x+1与直线l2:y=mx+n相交于点P(a,2),则关于x的不等式x+1<mx-n的解集为( )
| A. | x<m | B. | x<2 | C. | x<1 | D. | x>1 |
6.在一个直角三角形中,若两直角边长分为5cm,12cm,则下列结论不正确的是( )
0 296942 296950 296956 296960 296966 296968 296972 296978 296980 296986 296992 296996 296998 297002 297008 297010 297016 297020 297022 297026 297028 297032 297034 297036 297037 297038 297040 297041 297042 297044 297046 297050 297052 297056 297058 297062 297068 297070 297076 297080 297082 297086 297092 297098 297100 297106 297110 297112 297118 297122 297128 297136 366461
| A. | 斜边长为13cm | B. | 周长为25cm | ||
| C. | 面积为30cm2 | D. | 斜边上的中线长为6.5cm |