15.∠α=35°,则∠α的余角的度数为( )
| A. | 65° | B. | 55° | C. | 45° | D. | 25° |
14.方程x+1=3的解是( )
| A. | x=0 | B. | x=1 | C. | x=2 | D. | x=3 |
8.未来三年,国家将投入8450亿元用于缓解群众“看病难、看病贵”的问题.将8450亿元用科学记数法表示为( )亿元.
0 284109 284117 284123 284127 284133 284135 284139 284145 284147 284153 284159 284163 284165 284169 284175 284177 284183 284187 284189 284193 284195 284199 284201 284203 284204 284205 284207 284208 284209 284211 284213 284217 284219 284223 284225 284229 284235 284237 284243 284247 284249 284253 284259 284265 284267 284273 284277 284279 284285 284289 284295 284303 366461
| A. | 0.845×104 | B. | 8.45×103 | C. | 8.45×104 | D. | 84.5×102 |