3.若抛物线y=x2-2x+3不动,将平面直角坐标系xOy先沿水平方向向右平移一个单位,再沿铅直方向向上平移三个单位,则原抛物线图象的解析式应变为( )
| A. | y=(x-2)2+3 | B. | y=(x-2)2+5 | C. | y=x2-1 | D. | y=x2+4 |
2.下列等式一定成立的是( )
| A. | a2×a5=a10 | B. | $\sqrt{a+b}=\sqrt{a}+\sqrt{b}$ | C. | (-a3)4=a12 | D. | $\sqrt{a^2}=a$ |
18.下列计算结果正确的是( )
| A. | 2+$\sqrt{3}$=2$\sqrt{3}$ | B. | $\sqrt{8}÷\sqrt{2}$=2 | C. | (-2a2)3=-6a6 | D. | (a+1)2=a2+1 |
17.若2(a+3)的值与4互为相反数,则a的值为( )
0 284470 284478 284484 284488 284494 284496 284500 284506 284508 284514 284520 284524 284526 284530 284536 284538 284544 284548 284550 284554 284556 284560 284562 284564 284565 284566 284568 284569 284570 284572 284574 284578 284580 284584 284586 284590 284596 284598 284604 284608 284610 284614 284620 284626 284628 284634 284638 284640 284646 284650 284656 284664 366461
| A. | -1 | B. | -$\frac{7}{2}$ | C. | -5 | D. | $\frac{1}{2}$ |