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问题 选择题

函数y=2x-1的图象不经过（　　）

A．第一象限

B．第二象限

C．第三象限

D．第四象限

答案

∵k=2＞0，

∴函数y=2x-1的图象经过第一，三象限；

又∵b=-1＜0，

∴图象与y轴的交点在x轴的下方，即图象经过第四象限；

所以函数y=-x-1的图象经过第一，三，四象限，即它不经过第二象限．

故选B．

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