Hình hộp ABCD.A'B'C'D' có Aleft( 0;0;1 right),Bleft( - 1;1;0 right),Dleft( -

Ta có $\overrightarrow {AB} = \left( { - 1;1; - 1} \right),\,\,\overrightarrow {AD} = \left( { - 2; - 1; - 1} \right),\,\,\,\overrightarrow {AA'} = \left( {1;1; - 1} \right)$,
$\overrightarrow {AB} + \overrightarrow {AD} + \overrightarrow {AA'} = \overrightarrow {AC'} \Leftrightarrow \left( { - 2;1; - 3} \right) = \left( {{x_{C'}};{y_{C'}};{z_{C'}} - 1} \right) \Rightarrow C'\left( { - 2;1; - 2} \right).$