Ta có \(\dfrac{x}{19}=\dfrac{3xx}{19x3}=\dfrac{3x}{57x}\)
Lại có: \(\dfrac{x}{19}< \dfrac{12}{57}\)\(\Leftrightarrow\dfrac{3x}{57}< \dfrac{12}{57}\)\(\Leftrightarrow3x< 12\Leftrightarrow x=\left\{0;1;2;3\right\}\)
P/s Nhớ tick cho mình nha. Thanks bạn