Question

Tìm x biết: |x+1|+|x+2|+|x+3|=4x

Answer 1

ta có :

|x + 1| + |x +2| + |x + 3| = 4x

=> 3x + 6 = 4x

=>3x - 4x = - 6

=> - x = - 6

x = 6

Answer 2

Th1 :`x<0`

`=>4x<0`

Mà \(\left|x+1\right|+\left|x+2\right|+\left|x+3\right|\ge0\\ \Rightarrow\left|x+1\right|+\left|x+2\right|+\left|x+3\right|=4x\left(v\text{ô}.l\text{ý}\right)\)

Th2:`x>0`

\(\Leftrightarrow\left(x+1\right)+\left(x+2\right)+\left(x+3\right)=4x\\ \Leftrightarrow x+x+x-4x=-1-2-3\\ \Leftrightarrow-x=-6\\ \Rightarrow x=6\left(tm\right)\)