ГДЗ по геометрии 8 класс Атанасян Задание 767

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\[Дано:\ \]

\[\mathrm{\Delta}ABC;\ \]

\[\overrightarrow{a} = \overrightarrow{\text{AB}};\ \]

\[\overrightarrow{b} = \overrightarrow{\text{AC}}.\]

\[Выразить:\]

\[\textbf{а)}\ \overrightarrow{\text{BA}};\]

\[\textbf{б)}\ \overrightarrow{\text{CB}};\]

\[\textbf{в)}\ \overrightarrow{\text{CB}} + \overrightarrow{\text{BA}};\]

\[Решение.\]

\[\textbf{а)}\ \overrightarrow{\text{BA}}\ и\ \overrightarrow{\text{AB}} -\]

\[противоположные:\]

\[\overrightarrow{\text{BA}} = - \overrightarrow{\text{AB}}\]

\[\overrightarrow{\text{BA}} = - \overrightarrow{a}.\]

\[\overrightarrow{\text{CA}} = - \overrightarrow{\text{AC}};\]

\[\overrightarrow{\text{CB}} = \overrightarrow{\text{AB}} - \overrightarrow{\text{AC}} = \overrightarrow{a} - \overrightarrow{b}.\]

\[\overrightarrow{\text{CA}} = - \overrightarrow{\text{AC}} = - \overrightarrow{b}.\]