cho phương trình : (m - 1)x² + 2(m - 1)x - m = 0 ( ẩn x )

a) Định m để phương trình có nghiệm kép. Tính nghiệm kép này

b) Dịnh m để phương trình có hai nghiệm phân biệt đều âm

cho phương trình x² + 2x - 3 = 0 có 2 nghiệm là x₁ và x₂.

Không giải phương trình hãy tính giá trị của biểu thức sau :

A = \(\frac{6x_1^2+10x_1x_2+6x_2^2}{5x_1x_2^3+5x_1^3x_2}\)

B = \(\frac{3x_1^2+5x_1x_2+3x_2^2}{4x_1x_2^2+4x_1^2x_2}\)

giải phương trình :

a) \(x^2-\left(1+\sqrt{2}\right)x+\sqrt{2=0}\)

b) \(\sqrt{3}x^2-\left(1-\sqrt{3}\right)x-1=0\)

c) \(\left(2+\sqrt{3}\right)x^2-2\sqrt{3}-2 +\sqrt{3}=0\)

I. Complete the text with a/an, the, or zero article (X).
Hoàn thành bài khóa với a/an, the hoặc không sử dụng mạo từ (X).

Japan, a developed country in_______ Pacific Ocean, is becoming ______amazing destination to attract many travelers. One of _______ most attractive place is _________ Mount Fuji where visitors can enjoy a spectacular view of Japan from a height of 3,776 metres. It is not only ________ beauty spot for travelers to visit but also a challenge for climbing lovers to conquer. If tourists pay a visit to Japan in a day in _______ April, they can stop off at ________ Meguro River. They can go sailing and enjoy __________ picturesque scenery that is covered by the pinkness from the rows of cherry blossom trees. It is ________ perfectly beautiful picture to portray the spring in Japan. Furthermore, this country is considered a food paradise with many special dishes. Visitors can easily sample several traditional dishes such as sushi, ramen, tempura, sashimi and so on when dropping in at any restaurant in Piss Alley in _________ Tokyo. Japan is a promising land for those who are fond of exploring the unique beauty.

Read the passage and fill in each gap with a suitable word from the list: (1m)
crowds bought special interested seeing crowded
Last week when they came up to London, the Browns spent their time in (a)______ as much as
possible. Mrs. Brown was most (b)_______ in the stores, especially in Oxford Street, and
(c)______ some of the things which she could not find in the shops in the countryside. Their two
children, George and Susan, who had never been to London before, were surprised at the
(d)______ everywhere.

i only found out the truth because I heard hi speaking on the phone. (HAVE)

Complete the following text by writing ONE suitable preposition in each gap.

Cotton was cultivated in pakistan about 3,000 BC. It was also grown in Central America. Later it was also grown _____ Iraq and Egypt. The Industrial Revolution made cotton uch cheaper. In 1771 Richard Arkwright opened a cotton-spinning mill with a machine called a water frame, which was powered_____ a water mill. Then, in 1779, Samuel Crompton invented a new cotton-spinning machine called a spinning mule. Finally, in 1785 Edmund Cartwright invented a loom that could be powered by a steam engine. In 1794 American Eli Whitney patented the cotton gin. As a result_____ these new inventions cotton production boomed.

In 1884 Count Hilaire de Chardonnet made the first artificial fibre, from plant cellulose. In the following chemists invented new ways of making fibres_____ cellulose and by the 1920s they were common. The name rayon was invented in 1924.

Nylon was first made in 1935 by Wallace Carothers. Nylon stockings went_____ sale in 1940. Terylene was invented by British scientist John Rex Whinfield and James Tennant Dickson in 1941. Spandex was invented by Joseph Shivers in 1958. It was first manufactured in 1962

Read the passage and fill each gap with one suitable word

Christiaan Huygens spends Christmas day, in the Hague in 1656, contructing a model of a clock on a new principle. The principle ______ hes been observed by Galileo, traditionally as a result of watching a lamp swing to and fro in the cathedral when he is a student in Pisa. Galileo later proves experimentally that a swinging supspended object takes the ______ time to complete each swing regardless of how far it travels.

This consistency prompts Galileo to suggest that a pendulum might bu useful in clock. But no one has been able to apply that insight, until Huygens______ that his model works.

A craftsman in the Hague makes the first full-scale clock on this principle for Huygens in 1657. But it is England______ the idea is taken up with the greatest enthusiasm.

By 1600 London clockmakers have already developed the characteristic shape which makes______ use of the new mechanism - that of the longcase clock, more affectionately known as the grandfather clock