16.下列一元二次方程中,没有实根的是( )
| A. | x2+2x-3=0 | B. | x2+x+$\frac{1}{4}$=0 | C. | x2+$\sqrt{2}$x+1=0 | D. | -x2+3=0 |
15.计算(-1)×(-5)×(-$\frac{1}{5}$)的结果是( )
| A. | -1 | B. | 1 | C. | -$\frac{1}{25}$ | D. | -25 |
13.已知一次函数y=kx+b的图象与直线y=-x+1平行,且过点(1,-2),那么此一次函数的解析式为( )
| A. | y=-x+1 | B. | y=x-1 | C. | y=x+2 | D. | y=-x-1 |
12.已知a是实数,且关于x的二次方程x2+a2x+a=0有实根,则该方程的根x所能取的最大值是( )
0 308955 308963 308969 308973 308979 308981 308985 308991 308993 308999 309005 309009 309011 309015 309021 309023 309029 309033 309035 309039 309041 309045 309047 309049 309050 309051 309053 309054 309055 309057 309059 309063 309065 309069 309071 309075 309081 309083 309089 309093 309095 309099 309105 309111 309113 309119 309123 309125 309131 309135 309141 309149 366461
| A. | 0 | B. | 3$\sqrt{2}$ | C. | $\frac{\sqrt{2}}{2}$ | D. | $\frac{\root{3}{2}}{2}$ |