Mình có trả lời rồi bạn nhaa !

A.

1. It is sunny this weekend.

B.

My family went shopping tomorrow.

               will go

1. ...will be...

B:  (2)

A.

1. It is sunny this weekend.

B.

My family went shopping tomorrow.

               will go

\(B=x+\dfrac{1}{2}-\left|x-\dfrac{2}{3}\right|\)
Nhận xét:

\(\left|x-\dfrac{2}{3}\right|\ge x-\dfrac{2}{3},\forall x\\ \Rightarrow-\left|x-\dfrac{2}{3}\right|\le-\left(x-\dfrac{2}{3}\right)=-x+\dfrac{2}{3},\forall x\\ \Rightarrow x+\dfrac{1}{2}-\left|x-\dfrac{2}{3}\right|\le x+\dfrac{1}{2}-x+\dfrac{2}{3}=\dfrac{7}{6},\forall x\)
hay \(B\le\dfrac{7}{6},\forall x\)

Dấu "=" xảy ra khi và chỉ khi:
\(x-\dfrac{2}{3}=0\\ \Rightarrow x=\dfrac{2}{3}\)
Vậy...

A= 3 + 3² + 3³ + ... + 3¹⁰⁰
A= (3 + 3² + 3³ + 3⁴) + (3⁵ + 3⁶ + 3⁷ + 3⁸) + ... + (3⁹⁷ + 3⁹⁸ + 3⁹⁹ + 3¹⁰⁰)
A= 3.(1 + 3 + 3² + 3³) + 3⁵ . (1 + 3 + 3² + 3³) + ... + 3⁹⁷ . (1 + 3 + 3² + 3³)
A= 3 . 40 + 3⁵ . 40 + ... + 3⁹⁷ . 40
A= (3 + 3⁵ + 3⁹ + ... + 3⁹⁷) . 40
Mà 120 ⋮ 40
=> A= (3 + 3⁵ + 3⁹ + ... + 3⁹⁷) ⋮ 120
=> A ⋮ 120
Vậy A ⋮ 120

(x+2)(y-1)=133

=>\(\left(x+2;y-1\right)\in\left\{\left(1;133\right);\left(133;1\right);\left(-1;-133\right);\left(-133;-1\right);\left(7;19\right);\left(19;7\right);\left(-7;-19\right);\left(-19;-7\right)\right\}\)

=>\(\left(x;y\right)\in\left\{\left(-1;144\right);\left(131;2\right);\left(-3;-132\right);\left(-135;0\right);\left(5;20\right);\left(17;8\right);\left(-9;-18\right);\left(-21;-6\right)\right\}\)

b: (x-5)(y-2)=21

=>\(\left(x-5;y-2\right)\in\){(1;21);(21;1);(-1;-21);(-21;-1);(3;7);(7;3);(-3;-7);(-7;-3)}

=>\(\left(x;y\right)\in\){(6;23);(26;3);(4;-19);(-16;1);(8;9);(12;5);(2;-5);(-2;-1)}

1. is

2. is raining

3. doesn't like

4. is eating

5. drinks/has

6. isn't

1\(is\)

2\(is\) \(raining\)

3\(doesn't\) \(like\)

4\(is\) \(eating\)

5\(drinks\)/\(has\)

6\(isn't\)

(x+3)+(x+6)+...+(x+51)=493

=>17x+(3+6+...+51)=493

=>\(17x+3\left(1+2+...+17\right)=493\)

=>\(17x+3\cdot17\cdot\dfrac{18}{2}=493\)

=>\(17x+51\cdot9=493\)

=>17x=34

=>x=2

(x+2)+(x+4)+...+(x+20)=260

=>10x+(2+4+...+20)=260

=>\(10x+2\left(1+2+...+10\right)=260\)

=>\(10x+2\cdot10\cdot\dfrac{11}{2}=260\)

=>\(10x+110=260\)

=>10x=150

=>\(x=\dfrac{150}{10}=15\)

Số nhóm trong phép tỉnh tổng trên là: 

`(20 - 2) : 2 + 1 = 10` (nhóm)

`(x + 2) + (x+4) + ... + (x+20) = 260`

`=> 10x + (2+4+...+20) = 260`

`=> 10x + (20+2) . 10 = 260`

`=> 10x + 22. 10 = 260`

`=> 10x + 220 = 260`

`=> 10x = 260 - 220`

`=> 10x = 40`

`=> x = 40 : 10`

`=> x = 4`

Vậy `x = 4`

\(2n-1⋮2n+3\)

=>\(2n+3-4⋮2n+3\)

=>\(-4⋮2n+3\)

=>\(2n+3\in\left\{1;-1;2;-2;4;-4\right\}\)

=>\(2n\in\left\{-2;-4;-1;-5;1;-7\right\}\)

=>\(n\in\left\{-1;-2;-\dfrac{1}{2};-\dfrac{5}{2};\dfrac{1}{2};-\dfrac{7}{2}\right\}\)

\(2n+1⋮n+5\)

=>\(2n+10-9⋮n+5\)

=>\(-9⋮n+5\)

=>\(n+5\in\left\{1;-1;3;-3;9;-9\right\}\)

=>\(n\in\left\{-4;-6;-2;-8;4;-14\right\}\)

Ở thì hiện tại hoàn thành nhé mình cần gấp, cảm ơn các bạn 

1. She cooked the meal at this time yesterday.

cooked => was cooking 

2. His mother has just went to HCM city.

went => gone

3. What has she just say?

say => said

4. She's cuting grass in the garden now.

cuting => cutting

5. It's the first time he visits my family.

visits => has visited

6. When we came, they slept yesterday afternoon.

slept => were sleeping

7. Nam and his friend has found his keys.

has => have

8. I regret to inform that you fail the exam.

fail => have failed

9. She enjoyed collect stamp when she was young.

collect => collecting

10. We learn English for 3 years.

learn => have learned

11. She has been a nurse since she has graduated from the university.

has graduated => graduated

12. My mother is decorateing the room at the moment.

decorateing => decorating

13. She always is late for school.

always is => is always

14. My sister often doesn't go to the zoo on Monday.

often doesn't => doesn't often

15. His friends is tired today.

is = >are