18.某葡萄田2013年葡萄产量为100千克,估计2015年葡萄产量为144千克左右,若设葡萄田产量的年平均增长率为x,则根据题意可列方程为( )
| A. | 144(1-x)2=100 | B. | 100(1-x)2=144 | C. | 144(1+x)2=100 | D. | 100(1+x)2=144 |
17.在下列方程中,是一元二次方程的是( )
0 286591 286599 286605 286609 286615 286617 286621 286627 286629 286635 286641 286645 286647 286651 286657 286659 286665 286669 286671 286675 286677 286681 286683 286685 286686 286687 286689 286690 286691 286693 286695 286699 286701 286705 286707 286711 286717 286719 286725 286729 286731 286735 286741 286747 286749 286755 286759 286761 286767 286771 286777 286785 366461
| A. | x2+3x=$\frac{2}{x}$ | B. | 2(x-1)+x=2 | C. | x2=2+3x | D. | x2-x3+4=0 |