\(a,\dfrac{x}{y}-\dfrac{3}{8}=\dfrac{3}{2}\)
\(\dfrac{x}{y}=\dfrac{3}{2}+\dfrac{3}{8}\)
\(\dfrac{x}{y}=\dfrac{12}{8}+\dfrac{3}{8}\)
\(\dfrac{x}{y}=\dfrac{15}{8}\)
\(b,\dfrac{4}{9}:\dfrac{x}{y}=\dfrac{5}{3}\)
\(\dfrac{x}{y}=\dfrac{4}{9}:\dfrac{5}{3}\)
\(\dfrac{x}{y}=\dfrac{4}{9}\times\dfrac{3}{5}\)
\(\dfrac{x}{y}=\dfrac{12}{45}\)