\(a.\frac{1,5}{0,8}=\frac{\frac{3}{8}}{0,2x}\)
\(\Leftrightarrow\frac{15}{8}=\frac{15}{8x}\)
\(\Leftrightarrow8.15=15.8x\)
\(\Leftrightarrow8=8x\)
\(\Leftrightarrow x=1\)
\(b.8:\left(\frac{1}{4}x\right)=2:0,02\)
\(\Leftrightarrow\frac{8}{\frac{1}{4}x}=\frac{2}{\frac{1}{50}}\)
\(\Leftrightarrow\frac{32}{x}=100\)
\(\Leftrightarrow100x=32\)
\(\Leftrightarrow x=\frac{8}{25}\)