7.若x2-2x-5=0的一个解为a,则a(2a-3)+a(1-a)的值为( )
| A. | $\sqrt{6}$ | B. | 2$\sqrt{6}$+4 | C. | 5 | D. | -5 |
6.计算-1+2的结果是( )
0 284607 284615 284621 284625 284631 284633 284637 284643 284645 284651 284657 284661 284663 284667 284673 284675 284681 284685 284687 284691 284693 284697 284699 284701 284702 284703 284705 284706 284707 284709 284711 284715 284717 284721 284723 284727 284733 284735 284741 284745 284747 284751 284757 284763 284765 284771 284775 284777 284783 284787 284793 284801 366461
| A. | -3 | B. | 3 | C. | 1 | D. | -1 |