\[Стр.\ 35.\]
\[33.\ Основное\ свойство\ дроби\]
\[\boxed{\mathbf{1.}}\]
\[разделить;умножить;\]
\[\boxed{\mathbf{2.}}\]
\[7 = \frac{7}{1} = \frac{14}{2} = \frac{21}{3}.\]
\[\boxed{\mathbf{3.}}\]
\[\textbf{а)}\ \frac{2}{5} = \frac{6}{15}\]
\[\textbf{б)}\ \frac{12}{14} = \frac{6}{7}\]
\[\textbf{в)}\ \frac{15}{20} = \frac{3}{4}\]
\[\textbf{г)}\ \frac{48}{72} = \frac{24}{36}\]