\(3^2-5.\left[3.\left(4-1\right)-8\right]=9-5.\left(3.3-8\right)=9-5.\left(9-8\right)=9-5.1=9-5=4\)

\(\dfrac{1}{2}:\dfrac{3}{4}+\dfrac{1}{6}:\dfrac{3}{4}=\left(\dfrac{1}{2}+\dfrac{1}{6}\right):\dfrac{3}{4}=\left(\dfrac{3}{6}+\dfrac{1}{6}\right):\dfrac{3}{4}=\dfrac{2}{3}:\dfrac{3}{4}=\dfrac{2}{3}.\dfrac{4}{3}=\dfrac{8}{9}\)

\(x.\dfrac{1}{3}+x.\dfrac{1}{4}+x.\dfrac{1}{12}=6\)

\(x.\left(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{12}\right)=6\)

\(x.\dfrac{2}{3}=6\)

\(x=6:\dfrac{2}{3}\)

\(x=9\)