Question

x (31-x)=0

Answer 1

^^

Answer 2

\(x\left(31-x\right)=0\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\31-x=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\x=31\end{matrix}\right.\)

Answer 3

`x(31-x) =0`

`=>[(x=0),(31-x=0):}`

`=>[(x=0),(x=31):}`

Vậy `x in {0;31}`