11.如果不等式组$\left\{\begin{array}{l}{2x-5>3(x-1)}\\{-x<m}\end{array}\right.$的解集是无解,那么m的取值范围是( )
| A. | m=2 | B. | m≥2 | C. | m<2 | D. | m≤2 |
10.已知2a-y+5b3x与-5a2xb2+4y是同类项,则( )
| A. | $\left\{\begin{array}{l}{x=2}\\{y=-1}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{x=1}\\{y=-2}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x=3}\\{y=-2}\end{array}\right.$ |
9.下列命题中,真命题的是( )
| A. | 不是对顶角的两个角不相等 | |
| B. | 两条直线被第三条直线所截,内错角相等 | |
| C. | 若a>b,则|a|>|b| | |
| D. | 垂直于同一条直线的两直线平行 |
8.下列计算中,不正确的是( )
0 306740 306748 306754 306758 306764 306766 306770 306776 306778 306784 306790 306794 306796 306800 306806 306808 306814 306818 306820 306824 306826 306830 306832 306834 306835 306836 306838 306839 306840 306842 306844 306848 306850 306854 306856 306860 306866 306868 306874 306878 306880 306884 306890 306896 306898 306904 306908 306910 306916 306920 306926 306934 366461
| A. | a2•a5=a10 | B. | a2-2ab+b2=(a-b)2 | C. | -(a-b)=-a+b | D. | -3a+2a=-a |