20.函数y=$\sqrt{x-1}$+3中自变量的取值范围是( )
| A. | x≠1 | B. | x>1 | C. | x≥1 | D. | x≤1 |
12.
已知:如图,△ACB的面积为30,∠C=90°,BC=a,AC=b,正方形ADEB的面积为169,则(a-b)2的值为( )
0 284237 284245 284251 284255 284261 284263 284267 284273 284275 284281 284287 284291 284293 284297 284303 284305 284311 284315 284317 284321 284323 284327 284329 284331 284332 284333 284335 284336 284337 284339 284341 284345 284347 284351 284353 284357 284363 284365 284371 284375 284377 284381 284387 284393 284395 284401 284405 284407 284413 284417 284423 284431 366461
| A. | 25 | B. | 49 | C. | 81 | D. | 100 |