1) Hợp chất Z dc tảo bởi 2 nguyên tố M và X có công thức là M_aX_b. Trong đó M chiếm 46,67% về khối lượng. Trong hạt nhân nguyên tử M có N_M = P_M + 4. Còn trong hạt nhân của X có N_x = P_x. Biết rằng tổng số hạt proton trong phân tử Z bằng 58. Và a + b = 3 xác định công thức

Tìm GTLN của biểu thức

c)C = (2-x)(x+4)

d)\(\dfrac{7}{x^2-24x+215y}\)

Cho A= 4a²b² - (a² + b² - c²)²

Biết a, b, c là độ dài ba cạnh của tam giác. Chứng minh rằng A>0

Tìm GTNN của biểu thức

a) A= 2x^2- 3x +1

b) B= 4x² +7x + 13

c) C= 5-8x+x³

d) D=(x-1)(x+2)(x+3)(x+6)

1) Một phân tử chứa 2 nguyên tử M và nguyên tử X. Tổng các hạt trong phân tử là 116. Trong phân tử hạt mang điện nhiều hơn hạt không mang điện là 36. Nguyên tử khối của X > M là 9. Tổng số các loại hạt trong X nhiều hơn trong M là 13. Tìm số proton, tên nguyên tố và phân tử khối của X và Y

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 23 to 27.

Nowadays people are more aware that wildlife all over the world is in (23) _______. Many species of animals are threatened, and could easily become (24) _____ if we do not make an effort to protect them. In some cases, animals are hunted for their fur or for other valuable parts of their bodies. Some birds, such as parrots, are caught (25) _____ and sold as pets. For many animals and birds the problem is that their habitat - the place where they live - is disappearing. More land is used for farms, for houses or industry, and there  are fewer open spaces than there once were. Farmers use powerful chemicals to help them to grow better crops, but these chemicals pollute the environment and (26) _____ wildlife. The most successful animals on earth - human beings - will soon be the only ones (27) _____ unless we can solve this problem.

Điền vào ô 26.

A. spoil

B. wound

C. wrong

D. harm

Cho A(3;–2) ; B( 6; 9) và d: x+3y – 2 = 0. Nếu Đ d (A) = A’ , Đ d (B) = B’ thì A’B’ có độ dài bằng

A. 130

B. 130

C.11

D. Không đủ dữ kiện để tính

Read the following passage and blacken the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

        Sharks have gained an unfair reputation for being fierce predators of large sea animals. Humanity's unfounded fear and hatred of these ancient creatures is leading to a worldwide slaughter that may result in the extinction of many coastal shark species. The shark is the victim of a warped attitude of wildlife protection; we strive only to protect the beautiful, non-threatening parts of our environment. And, in our efforts to restore only non-threatening parts of our earth, we ignore other important parts.

        A perfect illustration of this attitude is the contrasting attitude toward another large sea animal, the dolphin. During the 1980s, environmentalists in the United States protested the use of driftnets for tuna fishing in the Pacific Ocean since these nets also caught dolphins. The environmentalists generated enough political and economic pressure to prevent tuna companies from buying tuna that had been caught in driftnets. In contrast to this effort on behalf of the dolphins, these same environmentalists have done very little to help save the Pacific Ocean sharks whose population has decreased nearly to the point of extinction.

Sharks are among the oldest creatures on earth, having survived in the seas for more than 350 million years. They are extremely efficient animals, feeding on wounded or dying animals, thus performing an important role in nature of weeding out the weaker animals in a species. Just the fact that species such as the Great White Shark have managed to live in the oceans for so many millions of years is enough proof of their efficiency and adaptability to changing environments. It is time for US humans, who may not survive another 1,000 years at the rate we are damaging the planet, to cast away our fears and begin considering the protection of sharks as an important part of a program for protection of all our natural environment.

The phrase “to cast away” means most nearly_____.

A. to throw off

B. to bring in

C. to see through

D. to set apart