Giải:
\(\left(2x-1\right)^2-\left(4x+1\right)\left(x-3\right)=3\)
\(\Leftrightarrow4x^2+4x-1^2-\left(4x^2-12x+x-3\right)=3\)
\(\Leftrightarrow4x^2+4x-1-4x^2+12x-x+3=3\)
\(\Leftrightarrow15x+2=3\)
\(\Leftrightarrow15x=3-2\)
\(\Leftrightarrow15x=1\)
\(\Leftrightarrow x=\dfrac{1}{15}\)
Vậy \(x=\dfrac{1}{15}\).
Chúc bạn học tốt!!!