\(\Leftrightarrow\frac{1}{x+2000}-\frac{1}{x+2007}=\frac{7}{\left(x+2000\right)\left(x+2007\right)}\)

\(\Rightarrow\frac{7}{\left(x+2000\right)\left(x+2007\right)}=\frac{7}{2^3}\)

\(\Rightarrow\frac{7\left(x^2+4007x+4013992\right)}{8\left(x+2000\right)\left(x+2007\right)}=0\)

áp dụng Delta ta có :

\(\Leftrightarrow x^2+4007x+4013992=0\)

\(\Rightarrow4007^2-4\left(1.4013992\right)=81\)

\(\Rightarrow x_{1,2}=\frac{-b+-\sqrt{D}}{2a}=\frac{-4007+-\sqrt{81}}{2}\)

=>x=-2008 hoặc -1999

2 đa thức trên vô nghiệm => ko phân tích thành nhân tử dc

Americans like sport very much. One of the (1) most popular kinds of sports in Autumn is football. All the high schools (2) and universities have their own teams.

In winter the most popular kind of sports (3) is basketball. There is usually a match every evening in one school gymnasium or another. In some parts of the United States there is a lot of (4) snow and ice. Many people like skiing and skating.

In the other two (5) seasons, millions of Americans enjoy baseball. The schools have their games in (6) spring, but the most important professional games are played during summer. Many people listen to the games (7) on the radio, watch them on television or read about them (8) in the newspapers.

Some also play tennis or golf and others (9) go fishing. They like to stay outdoors (10) because.it is warm during the months of June, July and August.

0. A. sees B. sports C. pools D. trains

1. A. neighbors B. friends C. relatives D. photographs

2. A. snacks B. follows C. tites D. writers

3. A. steets B. phones C. books D. makes

4. A. cities B. satellites C. series D. workers

5. A. develops B. takes C. laughs D. volumes

Đây là câu hỏi bá đạo nhất năm !!!!!!!!