9.有一道题:“化简求值:(2a+1)(2a-1)+(a-2)2-4(a+1)(a-2),其中a=-2”.小凡在解题时把“a=-2”抄成了“a=2”,但计算的结果与正确答案一致,请你通过计算加以说明.
2.已知a,b分别是6-$\sqrt{13}$的整数部分和小数部分,那么2a-b的值是( )
0 294295 294303 294309 294313 294319 294321 294325 294331 294333 294339 294345 294349 294351 294355 294361 294363 294369 294373 294375 294379 294381 294385 294387 294389 294390 294391 294393 294394 294395 294397 294399 294403 294405 294409 294411 294415 294421 294423 294429 294433 294435 294439 294445 294451 294453 294459 294463 294465 294471 294475 294481 294489 366461
| A. | $\sqrt{13}$ | B. | 6$\sqrt{2}$+2$\sqrt{3}$ | C. | 6$\sqrt{2}$+4$\sqrt{3}$ | D. | 以上答案都不对 |