A:x+-4×3
B:x--4×3
C:3x+-4
D:3x+4
函数f(x)=log0.8(2x2﹣ax+3)在(﹣1,+∞)为减函数,则a的范围( )
It's reported that people throw plastic bags along this street every day.
已知关于x的一元二次方程x2-kx-4=0的一个根为2,则另一根是( )