Question

tìm các giá trị của x để:|x+3|+|x+1|=3x

Answer 1

\(\left|x+3\right|+\left|x+1\right|=3x\)

\(\Leftrightarrow\left|x+3\right|=3x-\left|x+1\right|\)

\(\Leftrightarrow\left[{}\begin{matrix}x+3=3x-\left(x+1\right)\\x+3=3x-\left[-\left(x+1\right)\right]\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=\dfrac{2}{3}\end{matrix}\right.\)

Answer 2