A:x<3
B:x≥2
C:2≤x<3
D:2<x<3
0<a≤15是函数fx=ax2+2a-1x+2在区间(-∞,4上为减函数的( )
—Yes,I have.It was written by a celebrated writer,Yan Geling.
某同学在学习了杠杆和滑轮的知识后,细心观察了生活中现象,并提出下列说法,其中错误的是.( )