\[\boxed{\mathbf{649.}ОК\ ГДЗ\ –\ домашка\ на\ 5}\]
\[\overrightarrow{a}\left\{ 2;0;0 \right\};\ \ \overrightarrow{b}\left\{ - 3;5;7 \right\};\ \ \]
\[\overrightarrow{c}\left\{ - 0,3;0;1,75 \right\}.\]
\[Все\ знаки\ меняем\ на\ \]
\[противоположные.\]
\[- \overrightarrow{i}\left\{ - 1;0;0 \right\};\]
\[- \overrightarrow{j}\left\{ 0; - 1;0 \right\};\]
\[- \overrightarrow{k}\left\{ 0;0; - 1 \right\};\]
\[- \overrightarrow{a}\left\{ - 2;0;0 \right\};\]
\[- \overrightarrow{b}\left\{ 3; - 5;7 \right\};\]
\[- \overrightarrow{c}\left\{ 0,3;0; - 1,75 \right\}.\]