B. Z X YI 5( )X Y IX YI I5[( ( 1) ) Z I I5( )   ( 1) 21...

Câu 9b. z x yi 5( )x y ix yi i5[( ( 1) ) z i i   ( 1) 21 2x yi ix yi iÛ   z5x 5(y 1)i 2(x 1) (x 1)i 2yi yÛ         Û 5x 5(y1)i(2x 2 y) ( x 1 2 )y i3 2x1x y2 2 5x y x    Û Û  7 6x y yx y1 2 5( 1)y    z = 1 + i; w  1 z z

²

 1 (1 ) (1 )i  i

²

    1 1 i 1 2i ( 1) _{ 2 3i} Þ w  4 9  13Hà Văn Chương, Lưu Nam Phát(Trung tâm LTĐH Vĩnh Viễn – TP.HCM)