11.定义:点A(x,y)为平面直角坐标系内的点,若满足x=y,则把点A叫做“平衡点”.例如:M(1,1),N(-2,-2)都是“平衡点”.当-1≤x≤3时,直线y=2x+m上有“平衡点”,则m的取值范围是( )
| A. | 0≤m≤1 | B. | -3≤m≤1 | C. | -3≤m≤3 | D. | -1≤m≤0 |
9.若m•23=26,则m=( )
| A. | 2 | B. | 6 | C. | 4 | D. | 8 |
7.下列计算正确的是( )
| A. | a2•a3=a6 | B. | y3÷y3=y | C. | 3m+3n=6mn | D. | (x3)2=x6 |
5.下列式子中不是整式的是( )
| A. | 9x | B. | $\frac{2b}{a}$ | C. | 0 | D. | $\frac{4b}{3}$-5a |
3.下列函数中,自变量的取值范围选取错误的是( )
0 285478 285486 285492 285496 285502 285504 285508 285514 285516 285522 285528 285532 285534 285538 285544 285546 285552 285556 285558 285562 285564 285568 285570 285572 285573 285574 285576 285577 285578 285580 285582 285586 285588 285592 285594 285598 285604 285606 285612 285616 285618 285622 285628 285634 285636 285642 285646 285648 285654 285658 285664 285672 366461
| A. | y=x+2中,x取任意实数 | B. | y=$\sqrt{x+1}$中,x取x≤-1的实数 | ||
| C. | y=$\frac{1}{x+2}$中,x取x≠-2的实数 | D. | y=$\sqrt{{x}^{2}+1}$中,x取任意实数 |