1. a. plays b. looks c. wants d. helps

2. a. books b. things c. programs d. rulers

3. a. serious b. symptom c. sauce d. sugar

4. a. horrible b. hour c. hundred d. hold

5. a. touched b. laughed c. talked d. rented

1a

2a

3d

4b

5d

Help 😭

1. I hope I ___________the exam.

a. will pass b. pass c. will passes d. am passing

2. He’s famous_____________ his invention.

a. of b. about c. for d. on

3. My father will _______________ me to the zoo tomorrow.

a. taking b. to take c. takes d. take

4. He enjoys_____________TV in his free time.

a. watching b. to watch c. watches d. wach

5. She goes swimming________________.

a. everyday b. everydays c. every day d. every Sundays

6. They ____________at home yesterday.

a. were b. was c. are d. is

7. We ______________ some flowers tomorrow.

a. will buy b. buy c. bought d. buying

8. Look! He _____________to music.

a. is listening b. listens c. are listening d. listen

9. _____________he eats breakfast, he will be hungry.

a. If b. Unless c. If not d. Because

10. If you don’t eat, you ____________hungry.

a. will b. are c. will be d. is

11. After supper, he went on_____________________ his homework.

a. do b. doing c. did d. does

12. I will tell him about it as soon as he_________________ back.

a. comes b. will come c. come d. to come

13. It was too late, so I had to go home_____________________ a hurry.

a. with b. on c. in d. for

14. He is working hard now, but he used to__________ very lazy.

a. was b. being c. is d. be

15. His father often makes him__________________ up early.

a. get b. to get c. gets d. getting

16. I like to travel _______________ a train.

a. on b. with c. through d. by

17. When you __________________ her, you will agree with me about it.

a. meet b. have meeting c. are meeting d. would meet

18. Look! Someone ______________________.

a. is coming b. are coming c. come d. coming

\(#FallenAngel\)

1. I hope I ___________the exam.

a. will pass b. pass c. will passes d. am passing

2. He’s famous_____________ his invention.

a. of b. about c. for d. on

3. My father will _______________ me to the zoo tomorrow.

a. taking b. to take c. takes d. take

4. He enjoys_____________TV in his free time.

a. watching b. to watch c. watches d. wach

5. She goes swimming________________.

a. everyday b. everydays c. every day d. every Sundays

6. They ____________at home yesterday.

a. were b. was c. are d. is

7. We ______________ some flowers tomorrow.

a. will buy b. buy c. bought d. buying

8. Look! He _____________to music.

a. is listening b. listens c. are listening d. listen

9. _____________he eats breakfast, he will be hungry.

a. If b. Unless c. If not d. Because

10. If you don’t eat, you ____________hungry.

a. will b. are c. will be d. is

11. After supper, he went on_____________________ his homework.

a. do b. doing c. did d. does

12. I will tell him about it as soon as he_________________ back.

a. comes b. will come c. come d. to come

13. It was too late, so I had to go home_____________________ a hurry.

a. with b. on c. in d. for

14. He is working hard now, but he used to__________ very lazy.

a. was b. being c. is d. be

15. His father often makes him__________________ up early.

a. get b. to get c. gets d. getting

16. I like to travel _______________ a train.

a. on b. with c. through d. by

17. When you __________________ her, you will agree with me about it.

a. meet b. have meeting c. are meeting d. would meet

18. Look! Someone ______________________.

a. is coming b. are coming c. come d. coming

1. I hope I ___________the exam.

a. will pass b. pass c. will passes d. am passing

2. He’s famous_____________ his invention.

a. of b. about c. for d. on

3. My father will _______________ me to the zoo tomorrow.

a. taking b. to take c. takes d. take

4. He enjoys_____________TV in his free time.

a. watching b. to watch c. watches d. wach

5. She goes swimming________________.

a. everyday b. everydays c. every day d. every Sundays

6. They ____________at home yesterday.

a. were b. was c. are d. is

7. We ______________ some flowers tomorrow.

a. will buy b. buy c. bought d. buying

8. Look! He _____________to music.

a. is listening b. listens c. are listening d. listen

9. _____________he eats breakfast, he will be hungry.

a. If b. Unless c. If not d. Because

1. I hope I ___________the exam.

a. will pass b. pass c. will passes d. am passing

2. He’s famous_____________ his invention.

a. of b. about c. for d. on

3. My father will _______________ me to the zoo tomorrow.

a. taking b. to take c. takes d. take

4. He enjoys_____________TV in his free time.

a. watching b. to watch c. watches d. wach

5. She goes swimming________________.

a. everyday b. everydays c. every day d. every Sundays

6. They ____________at home yesterday.

a. were b. was c. are d. is

7. We ______________ some flowers tomorrow.

a. will buy b. buy c. bought d. buying

8. Look! He _____________to music.

a. is listening b. listens c. are listening d. listen

9. _____________he eats breakfast, he will be hungry.

a. If b. Unless c. If not d. Because

10. If you don’t eat, you ____________hungry.

a. will b. are c. will be d. is

11. After supper, he went on_____________________ his homework.

a. do b. doing c. did d. does

12. I will tell him about it as soon as he_________________ back.

a. comes b. will come c. come d. to come

13. It was too late, so I had to go home_____________________ a hurry.

a. with b. on c. in d. for

14. He is working hard now, but he used to__________ very lazy.

a. was b. being c. is d. be

15. His father often makes him__________________ up early.

a. get b. to get c. gets d. getting

16. I like to travel _______________ a train.

a. on b. with c. through d. by

17. When you __________________ her, you will agree with me about it.

a. meet b. have meeting c. are meeting d. would meet

18. Look! Someone ______________________.

a. is coming b. are coming c. come d. coming

1. I hope I ___________the exam.

a. will pass b. pass c. will passes d. am passing

2. He’s famous_____________ his invention.

a. of b. about c. for d. on

3. My father will _______________ me to the zoo tomorrow.

a. taking b. to take c. takes d. take

4. He enjoys_____________TV in his free time.

a. watching b. to watch c. watches d. wach

5. She goes swimming________________.

a. everyday b. everydays c. every day d. every Sundays

6. They ____________at home yesterday.

a. were b. was c. are d. is

7. We ______________ some flowers tomorrow.

a. will buy b. buy c. bought d. buying

8. Look! He _____________to music.

a. is listening b. listens c. are listening d. listen

9. _____________he eats breakfast, he will be hungry.

a. If b. Unless c. If not d. Because

x+(x+1)+(x+2)+...+(x+10)=88

=>11x+(1+2+...+10)=88

=>11x+55=88

=>x+5=8

=>x=3

Bài 1:

\(\dfrac{x-2}{5}=\dfrac{-2}{2y+1}\)

=>\(\left(x-2\right)\left(2y+1\right)=5\cdot\left(-2\right)=-10\)

mà 2y+1 lẻ

nên \(\left(x-2;2y+1\right)\in\left\{\left(2;-5\right);\left(-2;5\right);\left(-10;1\right);\left(10;-1\right)\right\}\)

=>\(\left(x;y\right)\in\left\{\left(4;-3\right);\left(0;2\right);\left(-8;0\right);\left(12;-1\right)\right\}\)

Bài 2:

a: \(\left(2x-1\right)^2+4>=4\forall x\)

=>\(B=\dfrac{20}{\left(2x-1\right)^2+4}< =\dfrac{20}{4}=5\forall x\)

Dấu '=' xảy ra khi 2x-1=0

=>\(x=\dfrac{1}{2}\)

b: \(\left(x^2+1\right)^2>=1\forall x\)

=>\(\left(x^2+1\right)^2+5>=1+5=6\forall x\)

=>\(C=\dfrac{10}{\left(x^2+1\right)^2+5}< =\dfrac{10}{6}=\dfrac{5}{3}\forall x\)

Dấu '=' xảy ra khi x=0

BÀI 4A

\(\dfrac{1}{-2}+\dfrac{1}{-6}+\dfrac{1}{-12}+\dfrac{1}{-20}+\dfrac{1}{-30}+\dfrac{1}{-42}+\dfrac{1}{-56}+\dfrac{1}{-72}+\dfrac{1}{-90}\\ =-1\cdot\left(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+\dfrac{1}{3\cdot4}+\dfrac{1}{4\cdot5}+\dfrac{1}{5\cdot6}+\dfrac{1}{6\cdot7}+\dfrac{1}{7\cdot8}+\dfrac{1}{8\cdot9}+\dfrac{1}{9\cdot10}\right)\\ =-1\cdot\left(\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\right)\\ =-1\cdot\left(\dfrac{1}{1}-\dfrac{1}{10}\right)=-1\cdot\dfrac{9}{10}=-\dfrac{9}{10}\)

\(\dfrac{3}{5}:\dfrac{7}{3}+\dfrac{3}{5}:\dfrac{7}{4}-1\dfrac{3}{5}\)

\(=\dfrac{3}{5}\cdot\dfrac{3}{7}+\dfrac{3}{5}\cdot\dfrac{4}{7}-1-\dfrac{3}{5}\)

\(=\dfrac{3}{5}-1-\dfrac{3}{5}=-1\)

Gọi số cam ban đầu trong rổ là \(x\) (quả)  \(\left(x\inℕ^∗\right)\)

Theo đề bài ta có:

\(x-\left(\dfrac{3}{5}x+5\right)=9\)

\(\Rightarrow x-\dfrac{3}{5}x-5=9\)

\(\Rightarrow x-\dfrac{3}{5}x=9+5\)

\(\Rightarrow\dfrac{2}{5}x=14\)

\(\Rightarrow x=14:\dfrac{2}{5}\)

\(\Rightarrow x=35\) (thỏa mãn điều kiện)

Vậy...

9 quả còn lại cộng 5 quả = 14 quả sẽ bằng \(\dfrac{2}{5}\) số cam

Số cam ban đầu ở rổ: 14: \(\dfrac{2}{5}\) = 35 quả

\(1+2+3+...+x=55\)

=>\(x\cdot\dfrac{\left(x+1\right)}{2}=55\)

=>x(x+1)=110

=>\(x^2+x-110=0\)

=>(x+11)(x-10)=0

=>\(\left[{}\begin{matrix}x+11=0\\x-10=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-11\left(loại\right)\\x=10\left(nhận\right)\end{matrix}\right.\)

Vậy: x=10

\(1+2+3+...+x=55\)

\(\dfrac{x\left(x+1\right)}{2}=55\)

\(x\left(x+1\right)=2\cdot55=110\)

\(x^2+x-110=0\)

\(x^2-10x+11x-110=0\\ x\left(x-10\right)+11\left(x-10\right)=0\\ \left(x-10\right)\left(x+11\right)=0\\ \left[{}\begin{matrix}x=10\\x=-11\end{matrix}\right.\)

cái gì đen thui vậy ?//

[Đề sau khi đã khôi phục:]

Tìm số tự nhiên n để các số: 

a) p = n * (n + 2) là số nguyên tố

b) q = (n - 2) * (n^2 + n + 5)