14.下列运算结果正确的是( )
| A. | a3+a2=a5 | B. | (x+y)2=x2+y2 | C. | x8÷x2=x4 | D. | (ab)2=a2b2 |
13.如果盈利20元记作+20,那么亏本50元记作( )
| A. | +50元 | B. | -50元 | C. | +20元 | D. | -20元 |
11.
某市一周的日最高气温如图所示,则该市这周的日最高气温的众数是( )
| A. | 25 | B. | 26 | C. | 27 | D. | 28 |
10.已知关于x的一元二次方程x2+3x+k=0有实数根,则下列四个数中,满足条件的k值为( )
0 284674 284682 284688 284692 284698 284700 284704 284710 284712 284718 284724 284728 284730 284734 284740 284742 284748 284752 284754 284758 284760 284764 284766 284768 284769 284770 284772 284773 284774 284776 284778 284782 284784 284788 284790 284794 284800 284802 284808 284812 284814 284818 284824 284830 284832 284838 284842 284844 284850 284854 284860 284868 366461
| A. | 2 | B. | 3 | C. | 4 | D. | 5 |