`\text{~~Holi~~}`
`|x|+x<1`
`->`\(\left[ \begin{array}{l}x+x<1, x\ge0\\-x+x<0, x<0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x<\dfrac{1}{2}, x\ge0\\x\in\mathbb{R}, x<0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x\in[0,\dfrac{1}{2})\\x\in(-∞,0)\end{array} \right.\)
`-> x\in(-∞,1/2)`