6.下面计算正确的是( )
| A. | 6a-5a=1 | B. | a2+a2=2a4 | C. | -(a-b)=-a+b | D. | 2(a+b)=2a+b |
5.太阳的半径为696000千米,把696000这个数据用科学记数法表示为( )
0 284545 284553 284559 284563 284569 284571 284575 284581 284583 284589 284595 284599 284601 284605 284611 284613 284619 284623 284625 284629 284631 284635 284637 284639 284640 284641 284643 284644 284645 284647 284649 284653 284655 284659 284661 284665 284671 284673 284679 284683 284685 284689 284695 284701 284703 284709 284713 284715 284721 284725 284731 284739 366461
| A. | 696×103 | B. | 69.6×104 | C. | 6.96×105 | D. | 6.96×106 |