On the left side we have:
[tex]18-18=0[/tex]Then, on the right side:
[tex]\begin{gathered} 2\cdot\mleft\lbrace28-3\cdot(2+4\mright)\}=2\cdot\mleft\lbrace28-3\cdot(6\mright)\} \\ =2\cdot\mleft\lbrace28-18\mright\rbrace=2\cdot10=20 \end{gathered}[/tex]Therefore, since in the left side we have 0 and on the right side we have 20, the correct symbol would be < and the expression would be:
[tex]18-18<2\cdot\mleft\lbrace28-3\cdot(2+4\mright)\}[/tex]