\(a,x\times3,14=3,768\)
\(\Leftrightarrow x=3,768:3,14\)
\(\Leftrightarrow x=1,2\)
\(b,\dfrac{2}{3}\times x=\dfrac{1}{4}\)
\(\Leftrightarrow x=\dfrac{1}{4}:\dfrac{2}{3}\)
\(\Leftrightarrow x=\dfrac{1}{4}\times\dfrac{3}{2}\)
\(\Leftrightarrow x=\dfrac{3}{8}\)