Ta có: \(\frac{x^2}{x-1}< 3\)
\(\Leftrightarrow x^2< 3\left(x-1\right)\)
\(\Leftrightarrow x^2< 3x-3\)
\(\Leftrightarrow x^2-3x+3< 0\)
\(\Leftrightarrow x^2-2\cdot x\cdot\frac{3}{2}+\frac{9}{4}+\frac{3}{4}< 0\)
\(\Leftrightarrow\left(x-\frac{3}{2}\right)^2+\frac{3}{4}< 0\)(vô lý)
Vậy: \(x\in\varnothing\)