1) Tìm x thuộc N thỏa : 

16^x<128⁴

1)Bỏ ngoặc rồi tính

-(a-b-c)+(-c+b+a)-(a+b)

1) You must be ........... when you cross the road ( care )

2) My aunt has two ........... , a boy and a girl ( child ) 

3) September is the ...... month of the year ( nine  )

4) My father goes .......every morning . ( jog ) 

5) There is a ......... garden to the right of the house . ( beauty ) 

Chứng minh : 18.8ⁿ+17 là hợp số