I got instructions not to let anyone get into this room.
A:examples
B:orders
C:rules
D:voices
实验室制取氧气,可供选择的实验装置如图所示.
如图所示,以边长为2的等边△ABO的顶点O为坐标原点,点B在x轴上,则经过点A的反比例函数的表达式为____
函数y=21-x+1x中,自变量x的取值范围是____ .