2.某种禽流感病毒变异后的直径为0.00000018米,0.00000018米用科学记数法表示为( )
| A. | 1.8×10-5米 | B. | 0.18×10-6米 | C. | 1.8×10-7米 | D. | 18×10-8米 |
1.下面计算正确的是( )
0 297665 297673 297679 297683 297689 297691 297695 297701 297703 297709 297715 297719 297721 297725 297731 297733 297739 297743 297745 297749 297751 297755 297757 297759 297760 297761 297763 297764 297765 297767 297769 297773 297775 297779 297781 297785 297791 297793 297799 297803 297805 297809 297815 297821 297823 297829 297833 297835 297841 297845 297851 297859 366461
| A. | 4a-3a=1 | B. | a2+a3=a5 | C. | x6÷x3=x2 | D. | (-2a3)2=4a6 |