... MaxMA- MB = AB = 6,khi M (-1 4- ) CõuVIIa.(1im) Hóchocvit i ỡ z1 -z2 = 2- ù i z - z2 1- = ù z z ợ 0 ,25 ( ỡ z + (- z2) = 21 - i) i ợ z (- z2) = -( 4+ ) ị z1 vưz2 lcỏcnghimcaphngtrỡnh z -2 1 - i)z - ... (z1z2) ẻ{( 3- i + i), (- 1- i-3+ i) } b.Theochngtrỡnhnõngcao CõuVIb: (2, 0) 0 ,25 ỡ2x- y= -5 ( ) B =( BE) ầ ( BM) : ị B - 21 ợ7x- y= -1 5 ( ) A ( x y )A 12 ị A = ( x - y - A ) 1 1 0 ,25 0 ,25 0 ,25 x ... B1(031 ) 2 ù2x + y + z - 4= ợ 1 0 ,25 0 ,25 0 ,25 MA-MB = AM - MB Ê AB = 1 Du=xyra A, M,B thnghng (M ẻ (a )) M = AB ầ (a ) ỡ x =1+ t ) ( AB ) :ù y = 2- t , (a) : 2x + y+ z- 1= 0ị M (- 1 4-1 ù z =...