Giải thích các bước giải:
`a)`
`x/5=-4/10`
`=>x/5=-2/5`
`=>x=-2`
`b)`
`|x|=0`
`=>x=0`
`c)`
`|x+1 | =2/3`
`=>`\(\left[ \begin{array}{l}x+1=\dfrac{2}{3}\\x+1=\dfrac{-2}{3}\end{array} \right.\)
`=>`\(\left[ \begin{array}{l}x=\dfrac{2}{3}-1\\x=\dfrac{-2}{3}-1\end{array} \right.\)
`=>`\(\left[ \begin{array}{l}x=\dfrac{-1}{3}\\x=\dfrac{-5}{3}\end{array} \right.\)