19.已知长江比黄河长836千米,黄河长的6倍比长江长的5倍多1284千米.若设长江长x千米,黄河长y千米,则下列方程组能满足上述关系的是( )
| A. | $\left\{\begin{array}{l}{x-y=836}\\{6y=5x+1284}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x+y=836}\\{5x=6y+1284}\end{array}\right.$ | ||
| C. | $\left\{\begin{array}{l}{y-x=836}\\{6y-5x=1284}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{y-x=836}\\{5x-6y=1284}\end{array}\right.$ |
17.
如图所示,矩形ABCD中,AB=4,BC=$4\sqrt{3}$,点E是折线ADC上的一个动点(点E与点A不重合),点P是点A关于BE的对称点.在点E运动的过程中,使△PCB为等腰三角形的点E的位置共有( )
| A. | 2个 | B. | 3个 | C. | 4个 | D. | 5个 |
16.已知一次函数y=kx+b经过两点(x1,y1),(x2,y2),若k<0,则当x1<x2时,( )
| A. | y1<y2 | B. | y1>y2 | C. | y1=y2 | D. | 无法比较 |
15.等腰三角形的腰长是10,一腰上的高为6,则底边长为( )
| A. | $2\sqrt{10}$ | B. | $4\sqrt{5}$ | C. | $2\sqrt{10}$或$6\sqrt{10}$ | D. | $4\sqrt{5}$或$6\sqrt{10}$ |
13.点P(2m-1,3+m)在第二象限,则所有满足条件的整数m有( )
0 285760 285768 285774 285778 285784 285786 285790 285796 285798 285804 285810 285814 285816 285820 285826 285828 285834 285838 285840 285844 285846 285850 285852 285854 285855 285856 285858 285859 285860 285862 285864 285868 285870 285874 285876 285880 285886 285888 285894 285898 285900 285904 285910 285916 285918 285924 285928 285930 285936 285940 285946 285954 366461
| A. | 5个 | B. | 3个 | C. | 1个 | D. | 没有 |