3.x4-9因式分解正确的是( )
| A. | (x2+3)(x2-3) | B. | (x2+3)(x+3)(x-3) | C. | (x2+3)(x+$\sqrt{3}$)(x-$\sqrt{3}$) | D. | (x2+3)(x-$\sqrt{3}$) |
2.
如图,AB是⊙O的直径,且AB=2$\sqrt{2}$,AD是弦,∠DAB=22.5°,延长AB到点C,使得∠ACD=45°,则BC的长是( )
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| A. | 2$\sqrt{2}$-2 | B. | $\sqrt{2}$ | C. | 1 | D. | 2-$\sqrt{2}$ |