Bµi 1: ViÕt PTTS, PTCT cña ®êng th¼ng d : e) §i qua E(1;-1;2) vµ vu«ng gãc víi 2 ®t: 5 2 1 1 2 : 66 41: 1 − + = − = += −−= = zyx d tz ty tx d 2 vµ Híng dÉn )9;17;14( 21 =Λ= uuu d vtcpcã d d u d 1 u 2 u 21 uuu d Λ=⇒⊥⊥ 21 d d vµ d d NÕu M 0 . d 2 d 1