câu trả lời của bn giống mik thế

a)ab+ba

=a.10+b.1+b.10+a.1

=a.10+a.1+b.10+b.1

=a.(10+1)+b.(10.1)

=a.11+b.11

=11.(a+b)11(vì 1111)

b)ab - ba

= 10a + b - (10b + a)

= 10a + b - 10b - a

= 9a - 9b = 9(a - b)

Vậy ta suy ra 9(a - b) chia hết cho 9 hay ab - ba chia hết cho 9 (a > b)

dịch:Anh ấy chơi bóng chuyền mấy lần một tuần?

 coppy?

 He plays volleyball [three times a week].=How many times a week does he play volleyball?

(2x-3) (3x-1) + 5x-2=6²−6𝑥+1=8

37. Students are under ___considerable__ (consider) stress when studying for exams.

Everyone liked the book, and the critics said that it was definitely a ___success___ (succeed).