The given expression is :
[tex]\mleft\lbrace x\mright|x\leq-4.3\}[/tex]In the given expression x is less than equal to - 4.3
so, it's domain will lie from - infinity to - 4.3
Thus :
[tex]\text{ Interval Notation: (-}\infty,-4.2\rbrack[/tex]Answer :
[tex]\text{ Interval Notation: (-}\infty,-4.2\rbrack[/tex]