a. \(-\frac{3}{5}-x=\frac{1}{2}\Leftrightarrow x=-\frac{3}{5}-\frac{1}{2}\Leftrightarrow x=\frac{11}{10}\)
b. \(1-3\frac{1}{5}:x=3\frac{3}{4}\Leftrightarrow3\frac{1}{5}:x=1-3\frac{3}{4}\)
\(\Leftrightarrow\frac{16}{5}:x=-\frac{11}{4}\Leftrightarrow x=\frac{16}{5}:\left(-\frac{11}{4}\right)=-\frac{64}{55}\)
c.\(75\%-\frac{1}{5}.x=3.75\Leftrightarrow\frac{1}{5}x=0.75-3.75=-3\Leftrightarrow x=-3:\frac{1}{5}=-15\)