c) Nếu D ( x 0 ; y 0 ; z 0 ) thì −−→ D C = ( x 0 − 5 ; y 0 ; z 0 − 4 ) .

c) Nếu \(D\left( {{{\rm{x}}_0};{{\rm{y}}_0};{{\rm{z}}_0}} \right)\) thì \(\overrightarrow {{\rm{DC}}} = \left( {{{\rm{x}}_0} - 5;{{\rm{y}}_0};{{\rm{z}}_0} - 4} \right).\)