已知1<x<5,化简根号下x²-2x+1+根号下x²-10x+25.老师上课时在黑板上写的步骤是根号下x²-2x+1+根号下x²-10x+25=根号下(x-1)²+根号下(x-5)²=|x-1|+|x-5|.∵1<x<5,∴x-1>0,x-5<0,
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/06 16:24:15
![已知1<x<5,化简根号下x²-2x+1+根号下x²-10x+25.老师上课时在黑板上写的步骤是根号下x²-2x+1+根号下x²-10x+25=根号下(x-1)²+根号下(x-5)²=|x-1|+|x-5|.∵1<x<5,∴x-1>0,x-5<0,](/uploads/image/z/1664864-8-4.jpg?t=%E5%B7%B2%E7%9F%A51%EF%BC%9Cx%EF%BC%9C5%2C%E5%8C%96%E7%AE%80%E6%A0%B9%E5%8F%B7%E4%B8%8Bx%26%23178%3B-2x%2B1%2B%E6%A0%B9%E5%8F%B7%E4%B8%8Bx%26%23178%3B-10x%2B25.%E8%80%81%E5%B8%88%E4%B8%8A%E8%AF%BE%E6%97%B6%E5%9C%A8%E9%BB%91%E6%9D%BF%E4%B8%8A%E5%86%99%E7%9A%84%E6%AD%A5%E9%AA%A4%E6%98%AF%E6%A0%B9%E5%8F%B7%E4%B8%8Bx%26%23178%3B-2x%2B1%2B%E6%A0%B9%E5%8F%B7%E4%B8%8Bx%26%23178%3B-10x%2B25%3D%E6%A0%B9%E5%8F%B7%E4%B8%8B%EF%BC%88x-1%EF%BC%89%26%23178%3B%2B%E6%A0%B9%E5%8F%B7%E4%B8%8B%EF%BC%88x-5%EF%BC%89%26%23178%3B%3D%7Cx-1%7C%2B%7Cx-5%7C.%E2%88%B51%EF%BC%9Cx%EF%BC%9C5%2C%E2%88%B4x-1%EF%BC%9E0%2Cx-5%EF%BC%9C0%2C)
已知1<x<5,化简根号下x²-2x+1+根号下x²-10x+25.老师上课时在黑板上写的步骤是根号下x²-2x+1+根号下x²-10x+25=根号下(x-1)²+根号下(x-5)²=|x-1|+|x-5|.∵1<x<5,∴x-1>0,x-5<0,
已知1<x<5,化简根号下x²-2x+1+根号下x²-10x+25.老师上课时在黑板上写的步骤是
根号下x²-2x+1+根号下x²-10x+25=根号下(x-1)²+根号下(x-5)²=|x-1|+|x-5|.∵1<x<5,∴x-1>0,x-5<0,∴|x-1|=x-1,|x-5|=5-x,∴原式=x-1+5-x=4.我的疑问是:1.为什么等于完根号下(x-1)²+根号下(x-5)²后要等于|x-1|+|x-5|,题目条件中不是已经给出1<x<5了吗,为什么x-1还要加绝对值?2.为什么最后一步∴原式等于完x-1+5-x后要等于4?
这个4是怎么来的?
已知1<x<5,化简根号下x²-2x+1+根号下x²-10x+25.老师上课时在黑板上写的步骤是根号下x²-2x+1+根号下x²-10x+25=根号下(x-1)²+根号下(x-5)²=|x-1|+|x-5|.∵1<x<5,∴x-1>0,x-5<0,
1.你不加也可以,但是要说明理由∵1