14.下列长度的各组线段中,能组成三角形的是( )
| A. | 1,1,2 | B. | 3,7,11 | C. | 6,8,9 | D. | 2,6,3 |
12.化简(2+1)(22+1)(24+1)(28+1)得( )
| A. | 28-1 | B. | 216+1 | C. | 216-1 | D. | 264-1 |
11.多项式4x2+1加上一个一次单项式后是一个完全平方式,这个单项式应为( )
| A. | 4x | B. | -4x | C. | ±2x | D. | ±4x |
10.下列计算中,正确的是( )
| A. | (a+b)2=a2+b2 | B. | (x-3y)2=x2-3xy+9y2 | ||
| C. | (6a3-4a2+2a)÷2a=3a2-2a | D. | ab2÷a=b2 |
9.在实数$\sqrt{2}$,π,$\frac{3}{7}$,-$\root{3}{8}$,2.1616…,2.1010010001…(每两个1之间依次多1个0)中,无理数有( )
| A. | 2个 | B. | 3个 | C. | 4个 | D. | 5个 |
8.计算3x2•4x2,结果正确的是( )
| A. | 7x2 | B. | 7x4 | C. | 12x2 | D. | 12x4 |
7.16的算术平方根是( )
0 288618 288626 288632 288636 288642 288644 288648 288654 288656 288662 288668 288672 288674 288678 288684 288686 288692 288696 288698 288702 288704 288708 288710 288712 288713 288714 288716 288717 288718 288720 288722 288726 288728 288732 288734 288738 288744 288746 288752 288756 288758 288762 288768 288774 288776 288782 288786 288788 288794 288798 288804 288812 366461
| A. | 4 | B. | -4 | C. | ±4 | D. | 2 |