\[\boxed{\mathbf{573.}ОК\ ГДЗ\ –\ домашка\ на\ 5}\]
\[\textbf{а)}\ \overrightarrow{\text{CD}} = - \overrightarrow{\text{DC}}\ и\ \ \overrightarrow{\text{DB}} - \overrightarrow{\text{BD}}:\]
\[\overrightarrow{\text{AB}} = \overrightarrow{\text{AC}} + \overrightarrow{\text{CD}} + \overrightarrow{\text{DB}} =\]
\[= \overrightarrow{\text{AC}} - \overrightarrow{\text{DC}} - \overrightarrow{\text{BD}}.\]
\[\textbf{б)}\ \overrightarrow{\text{AD}} = - \overrightarrow{\text{DA}}:\ \]
\[\overrightarrow{\text{AB}} = \overrightarrow{\text{AD}} + \overrightarrow{\text{DC}} + \overrightarrow{\text{CB}} =\]
\[= - \overrightarrow{\text{DA}} + \overrightarrow{\text{DC}} + \overrightarrow{\text{CB}}.\]
\[\textbf{в)}\ \overrightarrow{\text{AD}} - \overrightarrow{\text{DA}};\ \ \overrightarrow{\text{DC}} = - \overrightarrow{\text{CD}};\ \ \overrightarrow{\text{CB}} =\]
\[= - \overrightarrow{\text{BC}}:\]
\[\overrightarrow{\text{AB}} = \overrightarrow{\text{AD}} + \overrightarrow{\text{DC}} + \overrightarrow{\text{CB}} =\]
\[= - \overrightarrow{\text{DA}} - \overrightarrow{\text{CD}} - \overrightarrow{\text{BC}}.\]