ê trả lời chi bạn không hiểu 

Phương trình 2 sin 2 2 x − 5 sin 2 x + 2 = 0 có hai họ nghiệm dạng  x = α + kπ , x = β + kπ 0 < α , β < π . Khi đó tích αβ  là

A. 5 π 2 36

B.  5 π 2 144

C. - 5 π 2 36

D.  - 5 π 2 144

Choose the letter A, B, C or D the word that has the underlined part different from others.

A. reduce

B. scatter

C. mankind

D. mixture

Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks.

Computers cannot make mistakes. Stories have been heard sometimes about computers paying people too much money or sending them (1)_____ for things they didn’t buy. These mistakes ae made by the programs. Some years ago an American computer-controlled rocket went (2)____ and had to be destroyed. The accident has been caused by a small mistake in one line of the program, which (3)______ the USA 18 million dollars. Criminals have found that “computer (4)_____ are a lot easier than robbing a bank.” Hundreds of millions of dollars are stolen from businesses every year by people (8)______ the information in computers.

Question 2.

A. ahead of schedule

B. out of control

C. to some extent

D. How fast food trigger liver damage

Read the following passage and put a word in the box in each of the blanks.

more – groups – communicate – musical – Therefore

Gong culture in the Central Highlands

For the ethnic (1) __________ of the Central Highlands, gongs are (2) __________ instruments of special power. It is believed that every gong is the symbol of a god who grows (3) __________ powerful as the gong gets older. (4) __________, gongs are associated with special occasions in people’s lives, such as the building of new houses, funerals, crop praying ceremonies, etc. The gong sound is a way to (5) __________ with the gods.

Question 1:

Có %mO = 100% - 28% - 24% = 48%
Vì MA = 12,5.MO2
=>MA = 12,5.16.2 = 400 (g/mol)
Khối lượng mỗi nguyên tố trong 1mol hợp chất A là:
mS = (%mS.MA)/100% = (24.400)/100 = 96 (g)
mFe = (%mFe.MA)/100% = (28.400)/100 = 112 (g)
mO = (%mO.MA)/100% = (48.400)/100 = 192 (g)
Số mol nguyên tử mỗi nguyên tố trong 1mol hợp chất A là:
nS = mS/MS = 96/32 = 3 (mol)
nFe = mFe/MFe = 112/56 = 2 (mol)
nO = mO/MO = 192/16 = 12 (mol)
Vì trong 1mol hợp chất A có 2mol nguyên tử Fe, 3mol nguyên tử S và 12mol nguyên tử O nên CTHH của hợp chất A là:
Fe2(SO4)3
Mình làm giúp th chứ không chắc đúng đâu nhé ^.^

rat can diem

nho ban nao tich gium minh nhe

minh rat cam on