化简|5x+根号x²|(x<0).

问题描述:

化简|5x+根号x²|(x<0).

因为x<0
所以|x |=-x
又因为根号x²= |x |
|5x+根号x²|
=|5x+|x| |
= |5x-x |
= |4x |
=-4x