19.A、B两地相距80km,已知乙的速度是甲的1.5倍,甲先由A去B,1小时后,乙再从A地出发去追甲,追到B地时,甲已早到20分钟,则甲的速度为( )
| A. | 40km/h | B. | 45km/h | C. | 50km/h | D. | 60km/h |
14.若a≠b,化简$\sqrt{2\sqrt{ab}-a-b}$的结果为( )
0 295760 295768 295774 295778 295784 295786 295790 295796 295798 295804 295810 295814 295816 295820 295826 295828 295834 295838 295840 295844 295846 295850 295852 295854 295855 295856 295858 295859 295860 295862 295864 295868 295870 295874 295876 295880 295886 295888 295894 295898 295900 295904 295910 295916 295918 295924 295928 295930 295936 295940 295946 295954 366461
| A. | $\sqrt{a}$-$\sqrt{b}$ | B. | -$\sqrt{a}$-$\sqrt{b}$ | C. | $\sqrt{-a}$+$\sqrt{-b}$ | D. | 0 |