问题
填空题
已知点A(1，3)，B(－2，－1)，若直线l：y＝k(x－2)＋1与线段AB相交，则k的取值范围是________．
答案
由题意知直线l恒过定点P(2，1)，如下图．
若l与线段AB相交，则kPA≤k≤kPB.∵ kPA＝－2，kPB＝
，∴ －2≤k≤.
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已知点A(1，3)，B(－2，－1)，若直线l：y＝k(x－2)＋1与线段AB相交，则k的取值范围是________．
由题意知直线l恒过定点P(2，1)，如下图．
若l与线段AB相交，则kPA≤k≤kPB.∵ kPA＝－2，kPB＝，∴ －2≤k≤.
| 补全对话。 A: My six-year-old sister started school this week. B: __1__ Life was great when I was six years old. A: Really? Why? B: __2__ Don't you think so? A: Not for me. I didn't like tests.__3__ B: __4__ Now we just study all the time. A: Yeah, but we walked to school. Now we can take the school bus. B: I remember one thing. __5__ Now I love art classes. A: Me, too.
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