ab + ba = 11a + 11b = 11(a+b) = 55

=> a + b = 55 : 11= 5

a + b = 1+4 = 2+3 

Vậy ab = 14 ; ba = 41 hoặc ab = 41 ; ab = 14

Hoặc ab = 32 ; ba = 23 hoặc ab = 23 ; ba = 32

? Đề là gì z bnn?

Bài 1:put a suitable preposition to complete the sentence:

1.I like taking part in sport

2.there was a walking competition for children last year

3.the number of participants increases every week

4.you should listen to the pool lifeguards

5.I don't have my pocket for me

6.are you aware for the time?

7.I'm really interested in Vietnamese history

8.I went to My parents near the zoo last sunday

Mk nghĩ là z