14.若-2amb4与5an+2b2m+n是同类项,则mn的值是( )
| A. | 2 | B. | 0 | C. | -1 | D. | 1 |
10.在一个不透明的袋中装着2个红球和1个黄球,它们除颜色外其它均相同,随机从袋中摸出2个小球,两球恰好都是红球的概率为( )
0 295117 295125 295131 295135 295141 295143 295147 295153 295155 295161 295167 295171 295173 295177 295183 295185 295191 295195 295197 295201 295203 295207 295209 295211 295212 295213 295215 295216 295217 295219 295221 295225 295227 295231 295233 295237 295243 295245 295251 295255 295257 295261 295267 295273 295275 295281 295285 295287 295293 295297 295303 295311 366461
| A. | $\frac{1}{2}$ | B. | $\frac{1}{3}$ | C. | $\frac{1}{4}$ | D. | $\frac{1}{6}$ |