3.下列各式由左到右的变形中,属于因式分解的是( )
0 282541 282549 282555 282559 282565 282567 282571 282577 282579 282585 282591 282595 282597 282601 282607 282609 282615 282619 282621 282625 282627 282631 282633 282635 282636 282637 282639 282640 282641 282643 282645 282649 282651 282655 282657 282661 282667 282669 282675 282679 282681 282685 282691 282697 282699 282705 282709 282711 282717 282721 282727 282735 366461
| A. | (x+2)(x-1)=x2+x-2 | B. | x2+x+1=(x+1)2-x | ||
| C. | -a2-ab-ac=-a(a+b+c ) | D. | a2+b2=(a+b)2-2ab |