... =0 ,25 PTtABl:AB A AB A xxxxyyyy - - = - - Thayy A ,yBtac:y)(4 124 00 A Axxyyx - = - 0 ,25 CõuVIA(2im)ThaytoimEv ptABtac:)4(4 124 100 A Axyyx - = - - 40 = yVycú1imt/mM(04)0 ,25 2. - Phơng ... tip imA,BlA(x A ,y A ),B(xB,yB)PTttMAl:(x A 4)(x4)+y A y=4Vỡtt iquaM(0y0)nờntacú4(x A 4)+y A y0=40 124 yxy A A - = ị0 ,25 Tngt:0 124 yxyBB - =0 ,25 PTtABl:AB A AB A xxxxyyyy ... 2b -a; 3b -a) 0 ,25 - Đờng thẳng d qua A, B ú( )AB ku A P ỡ = ù ớ ẽ ù ợ uuur r 2 314 a b ỡ = ù ù ớ ù = ù ợ0 ,25 2. (1im) - Vậy d : 2 2 2 3 3 31 2 1x y z - - - = = - 0 ,25 ...