Cân bằng phương trình sau:

4CO₂ + 3Ba(OH)₂ -> BaCO₃ +Ba(HCO₃)₂ + H₂O

Tính:

\(\sqrt{105}.\left(\sqrt{\frac{15}{7}}-\sqrt{\frac{35}{3}}+\sqrt{\frac{21}{5}}\right)\)

Bạn có học thầy Long trường THCS Lê Quý Đôn ,thành phố Hải Dương hay ko?

Bài 1: Tính giá trị biểu thức của:

a) A = \(\frac{5x^3-2x^2+2,5x-2,6}{x^2+3x-2,7}\) tại x = \(\sqrt{0,7}\)

b) B = \(\frac{2x^4-5x^3+2x^2-5x-30}{x^2+10x-15}\) tại x = \(-\sqrt{5}\)

c) C = \(\sqrt{x^4}-3\left(\sqrt{-x}\right)^3-2\sqrt{x^2}-5\sqrt{-x}+x\) tại x = -3

Bài 2: Phân tích biểu thức thành nhân tử:

a) \(3x-7\sqrt{x}-20\)

b) \(x^2-x\sqrt{x}-5x-\sqrt{x}-6\)

Bài 3: Giải phương trình:

a) \(3x-5\sqrt{x}=x-3\)

Bài 4: So sánh các số:

a) \(\sqrt{\frac{10}{17}}\) và \(\frac{3}{4}\)

b) \(1+\sqrt{15}\) và \(\sqrt{24}\)

I. Choose a word in each line that has different stress pattern:

1. A. famous B. village C. workshop D. bamboo

2. A. business B. experience C. grandparent D. chocolate

3. A. generation B. communicate C. historical D. environment

4. A. embroider B. department C. handicraft D. opinion

5. A. transfer B. publish C. accept D. remind

6. A. attraction B. artisan C. frame D. handicraft

7. A. drumhead B. illustration C. earplug D. drugstore

8. A. strip B. visual C. artistic D. remind

9. A. thread B. treat C. pleasure D. deadline

10. A. embroider B. preserve C. benefit D. effect

II. Find the word which has a different position of the main stress in each line :

1. A. craftman B. layer C. sculpture D. preserve

2. A. lacquerware B. absolute C. pollution D. permanent

3. A. memorable B. experience C. historical D. production

4. A. pottery B. souvenir C. conical D. various

5. A. authenticity B. electricity C. traditional D. uncontrollably

III. Give the correct form of the word in CAPITALS to complete each fo the following sentences:

1. There are a lot of silk __________ such as carves, ties and dresses in our shop. (PRODUCE)

2. Bat Trang is one of the famous _________ craft villages in Hanoi. (TRADITION)

3. We shoul read this leaflet to see what __________ are organized dring the festival. (ACT)

4. They show me a marble sculpture which was __________ made by hand. (SKILL)

5. Last week we had a __________ trip to an ancient village on the outskirts of Hanoi. (MEMORY)

6. Obviosly, our handicrafts are in __________ with those of other villages. (COMPETE)

7. Do you know that __________ have to follow15 stages to make a conical hat. (ART)

8. My grandfather has devoted himself to many _________ events in our community. (CULTURE)

9. You should spend at least one week to visit the tourist _________ in this city. (ATTRACT)

10. We are impressed by a wide _______ of lacquerwares in the showroom. (VARY).

Thực hiện các phép tính sau:

a)\(\frac{10+2\sqrt{10}}{\sqrt{5}+\sqrt{2}}+\frac{8}{1-\sqrt{5}}\)

b) \(\frac{2\sqrt{8}-\sqrt{12}}{\sqrt{18}-\sqrt{48}}-\frac{\sqrt{5}+\sqrt{27}}{\sqrt{30}+\sqrt{162}}\)

c) \(\sqrt{\frac{2-\sqrt{3}}{2+\sqrt{3}}}+\sqrt{\frac{2+\sqrt{3}}{2-\sqrt{3}}}\)

d) \(\frac{\sqrt{3-\sqrt{5}}.\left(3+\sqrt{5}\right)}{\sqrt{10}+\sqrt{2}}\)

e) \(\frac{1}{\sqrt{2}+\sqrt{2+\sqrt{3}}}+\frac{1}{\sqrt{2}-\sqrt{2-\sqrt{3}}}\)

f) \(\frac{\left(\sqrt{5}+2\right)^2-8\sqrt{5}}{2\sqrt{5}-4}\)