10.已知一次函数y=x+b图象经过两直线l1:x+2y-2=0,l2:2x+y-7=0的交点,则b的值为( )
| A. | 5 | B. | -5 | C. | 3 | D. | -3 |
9.
如图,AD是∠EAC的平分线,AD∥BC,∠C=25°,则∠B为( )
| A. | 45° | B. | 30° | C. | 25° | D. | 20° |
8.
如图,在△ABC中,DE∥BC,∠A=60°,∠ADE=50°,则∠C的度数为( )
| A. | 50° | B. | 60° | C. | 70° | D. | 80° |
7.一组数据为6,12,12,15,9,27,12,15,3,24,其众数、中位数及平均数分别是( )
| A. | 12,12,18 | B. | 12,12,13.5 | C. | 12,18,13.5 | D. | 15,18,13.5 |
6.$\sqrt{(-4)^{2}}$的平方根是( )
0 278859 278867 278873 278877 278883 278885 278889 278895 278897 278903 278909 278913 278915 278919 278925 278927 278933 278937 278939 278943 278945 278949 278951 278953 278954 278955 278957 278958 278959 278961 278963 278967 278969 278973 278975 278979 278985 278987 278993 278997 278999 279003 279009 279015 279017 279023 279027 279029 279035 279039 279045 279053 366461
| A. | 2 | B. | -2 | C. | ±2 | D. | ±4 |