a: \(\dfrac{1}{3}+\dfrac{3}{35}< \dfrac{x}{210}< \dfrac{4}{7}+\dfrac{3}{5}+\dfrac{1}{2}\)
\(\Leftrightarrow\dfrac{70}{210}+\dfrac{18}{210}< \dfrac{x}{210}< \dfrac{120}{210}+\dfrac{126}{210}+\dfrac{105}{210}\)
\(\Leftrightarrow88< x< 441\)
b: Ta có: \(\dfrac{5}{3}+\dfrac{-14}{3}< x< \dfrac{8}{5}+\dfrac{18}{10}\)
\(\Leftrightarrow\dfrac{5}{3}-\dfrac{14}{3}< x< \dfrac{8}{5}+\dfrac{9}{5}\)
=>-9/3<x<17/5
=>-3<x<3,4
mà x là số nguyên
nên \(x\in\left\{-2;-1;0;1;2;3\right\}\)