化简|2x+5|-|3x-7|.

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/16 08:47:43

化简|2x+5|-|3x-7|.
化简|2x+5|-|3x-7|.

化简|2x+5|-|3x-7|.
2x+5=0,x=-5/2;3x-7=0,x=7/3
分段讨论:
当x≤-5/2时,|2x+5|=-(2x+5),|3x-7|=-(3x-7),
|2x+5|-|3x-7|= |=-(2x+5)-(3x-7)=-2x-5-3x+7=-5x+2;
当-5/2x≤x≤7/3时,|2x+5|=2x+5,|3x-7|=-(3x-7),
|2x+5|-|3x-7|= |=2x+5-3x+7=-x+12;
当x≥7/3时,|2x+5|=2x+5,|3x-7|=3x-7,
|2x+5|-|3x-7|= |=2x+5+3x-7=5x-2;

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