17.若代数式2a+b=5,则代数式6a+3b+1的值是( )
| A. | 16 | B. | 22 | C. | 25 | D. | 无法计算 |
15.已知下列各式$\frac{x30%}{m}$,$\frac{a}{2}$,ah+2$\frac{2}{3}$x,3x+2,$\frac{1}{2}$x,a×2,其中不符合代数式书写规范的有( )
| A. | 3个 | B. | 4个 | C. | 5个 | D. | 6个 |
10.下列关于无理数的说法中,正确的是( )
0 286719 286727 286733 286737 286743 286745 286749 286755 286757 286763 286769 286773 286775 286779 286785 286787 286793 286797 286799 286803 286805 286809 286811 286813 286814 286815 286817 286818 286819 286821 286823 286827 286829 286833 286835 286839 286845 286847 286853 286857 286859 286863 286869 286875 286877 286883 286887 286889 286895 286899 286905 286913 366461
| A. | 有最小的无理数 | B. | 有最大的无理数 | C. | 无理数有有限个 | D. | 无理数有无限个 |