a, Ta có
\(\dfrac{111}{37}< x< \dfrac{91}{37}\Leftrightarrow3< x< 7\Leftrightarrow x\in\left\{4,5,6\right\}\)
b,Ta co
\(\dfrac{-84}{14}< 3x< \dfrac{108}{9}\Leftrightarrow3.\dfrac{-28}{14}< 3x< 3.\dfrac{36}{9}\Leftrightarrow\dfrac{-28}{14}< x< \dfrac{36}{9}\Leftrightarrow-2< x< 4\Leftrightarrow x\in\left\{-1,0,1,2,3\right\}\)