1 my heart aches when i think of that orphan boy.

2.your comment shows your lack of understanding.

3.David like coffee without milk or sugar
 

Nam Cao

1.My brother is lazy so he sometimes gets bad grade.

2.Do you know anything about Mary's husband ?

3.Jame lives not far from his school.

mình ghi cả câu

1.Mr.Brown often attends clean up campaigns

2. What a lovely day is !

1.

a)8¹⁰²-2¹⁰²

= 8² .8¹⁰⁰ - 2². 2¹⁰⁰

=64.(8⁴)²⁵-4.(2⁴)²⁵

=64 . ...6²⁵ - 4 . ...6²⁵

=....4 - ...4

.=...0 chia hết cho 10

b)3⁴ⁿ⁺¹+2

=(3⁴)ⁿ⁺¹ + 2

= ....1 + 2

=....3 chia hết cho 3

2.

a)C = 2.1+2.3+...+2.3²⁰⁰⁴

C = 2.(1+3+...+3²⁰⁰⁴)

đặt D=1+3+..+3²⁰⁰⁴

3D=3+ .....+32005

3D - D=3²⁰⁰⁵ - 3

2D=3²⁰⁰⁵-1

2D= (3⁴)501.3 - 1

2D = 81⁵⁰¹ .3 - 1

D= (...1 . 3- 1):2

D = (...3 - 1) :2

D= ...2 : 2

D=....1

b)B= 1+ 3+...+3³⁰⁰

3B= 3+...+3¹⁰¹

2D = 3¹⁰¹ - 1

D= (3¹⁰¹ - 1):2

D=(3¹⁰⁰.3-1):2

D=[(3⁴)²⁵. 3 -1]:2

D= [...1²⁵.3-1]:2

D= [...3-1]:2

D=...2:2

D=....1

ta có

10⁸ là 1 số chẵn:1000..0 có tổng các chữ số là 1

=>10⁸ +8=1000...8 có tổng các chữ số là9

=>10⁸ + 8 chia hết cho 2 và 9

=>10⁸+8 chia hết cho 18