First let's solve the inequation by isolating the variable x:
[tex]\begin{gathered} 2x\le x-9 \\ 2x-x\le-9 \\ x\le-9 \end{gathered}[/tex]
Now, writing the solution in the set-builder notation, we have:
[tex]\mleft\lbrace x\mright|x\le-9\}[/tex]
{x | x ≤ -9}
In the interval notation, we have:
[tex](\infty,-9\rbrack[/tex]
Outside editor: (∞, -9]
