Cho ∆ABC vuông cân tại A, cạnh AB=5, Tích vô hướng vecto BC . vecto BA bằng: 

 (Chi tiết giúp em với ạ)
 

her vocal are professional , or she has received many votes from the viewers
a. professional

b. or

c. has received

d. from

my father is talking the family to dalat every year when he has free time

a. is talking

b. to

c. when

d. has

. Daniela told me she had booked a tour of Europe _________.      

          A. the following day              B. the next day             C. the day after            D. the day before