8.
符合数轴所表示的解集的不等式组是( )
| A. | $\left\{\begin{array}{l}{x+1>0}\\{4-x>0}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x+1>0}\\{x-4>0}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{x+1<0}\\{x-4>0}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x+1<0}\\{4-x>0}\end{array}\right.$ |
7.
如图,点D,E在AB,AC上,连接DE,DF平分∠BDE交BC于点F,∠BDF+∠DFC=180°,∠AED=∠BFD.
(1)DE与BC平行吗?并写出理由;
(2)写出图中与∠CED相等的角及理由.
(1)DE与BC平行吗?并写出理由;
(2)写出图中与∠CED相等的角及理由.
2.
如图,将一副三角板叠合在一起(∠AOB=∠COD=90°,∠A=30°,∠C=45°),使直角顶点重合,AB与OC交于点E,若∠AOD=3∠BOC,则∠OEA的度数为( )
0 297069 297077 297083 297087 297093 297095 297099 297105 297107 297113 297119 297123 297125 297129 297135 297137 297143 297147 297149 297153 297155 297159 297161 297163 297164 297165 297167 297168 297169 297171 297173 297177 297179 297183 297185 297189 297195 297197 297203 297207 297209 297213 297219 297225 297227 297233 297237 297239 297245 297249 297255 297263 366461
| A. | 95° | B. | 105° | C. | 115° | D. | 120° |