on ptdt

Bµi 1: ViÕt PTTS, PTCT cña ®­êng th¼ng d: c) §i qua B(1 ; 2 ; 3) vµ C(5 ; 4 ; 4) )1;2;4(== BC d u vtcpcã d BCu d =⇒ CB,qua d NÕu d B . C . H­íng dÉn