Bài 1:

\(\left(x-2013\right)^{2014}=1\)

\(\Leftrightarrow\orbr{\begin{cases}x-2013=1\\x-2013=-1\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2014\\x=2012\end{cases}}}\)

Vậy x=2014; x=2012

Bài 2: 

a) Ta có: \(2^{333}=\left(2^3\right)^{111}=8^{111}\)

\(3^{222}=\left(3^2\right)^{111}=9^{111}\)

Ta thấy 8<9 => \(8^{111}< 9^{111}\Rightarrow2^{333}< 3^{222}\)

b) Ta có: \(9^{1005}=\left(3^2\right)^{1005}=3^{2010}\)

Ta thấy \(3^{2009}< 3^{2010}\Rightarrow3^{2009}< 9^{1005}\)

c) \(99^{20}=\left(99^2\right)^{10}=9801^{10}\)

Thấy \(9801< 9999\Rightarrow9801^{10}< 9999^{10}\Rightarrow99^2< 9999^{10}\)

B1:                                                                                                                                                                                                                            (x-2013)²⁰¹⁴=1                                                                                                                                                                                                =>x-2013=1;-1=>x=2014;2012                                                                                                                                                                          B2:                                                                                                                                                                                                                       a)có:2³³³=(2³)¹¹¹=8¹¹¹ ;  3²²²=(3²)¹¹¹=9¹¹¹                                                                                                                                                         =>2³³³<3²²²(8¹¹¹<9¹¹¹)                                                                                                                                                              b)có:9¹⁰⁰⁵=(3²)¹⁰⁰⁵=3²⁰¹⁰ >3²⁰⁰⁹                                                                                                                                                                      =>9¹⁰⁰⁵>3²⁰⁰⁹                                                                                                                                                                                             c)có:99²⁰=(99²)¹⁰=9801¹⁰<9999¹⁰                                                                                                                                                                    =>99²⁰<9999¹⁰

Which of the followings is NOT true ?

a. Only big cities have the problem of pollution 

b.Traffic jams cause pollution 

c.Pollution is a major problem in big cities 

d.Pollution causes health and enviromental problems 

1. The roads in VN are too narrow for us to travel easily.

2. It's very important to obey traffic rules when using the road.

3. Two days ago we got stuck in the traffic jam for over two hours.

4. Most streets in the city centre are congested during rush hours.

A = 1 nha

1. There is a good.............................of meat on the stall

A. kind             B. selection        C. type              D. stall

2. ....................he..................last semester?-Very well.

A. How/ studied       B. How did / studied  C. How does / study    D. How did /study

3. An speaks....................................

A. English perfect     B. English perfectly   C. perfectly English     D. perfected English

4. The dentist......................a cavity in Nam's tooth last Sunday.

A. pulled            B. drilled           C. Washed           D. filled

5. Liz never goes to school late and I.....................

A. didn't either        B. don't too         C. neither do         D. don't either

Choose the best answer (A, B, C or D) for each sentence below

1. There is a good.............................of meat on the stall

A. kind             B. selection        C. type              D. stall

2. ....................he..................last semester?-Very well.

A. How/ studied       B. How did / studied  C. How does / study    D. How did /study

3. An speaks....................................

A. English perfect     B. English perfectly   C. perfectly English     D. perfected English

4. The dentist......................a cavity in Nam's tooth last Sunday.

A. pulled            B. drilled           C. Washed           D. filled

5. Liz never goes to school late and I.....................

A. didn't either        B. don't too         C. neither do         D. don't either

Vì \(\Delta ABC\) vuông tại A \(\Rightarrow\widehat{A}=90^0\Leftrightarrow BC^2=AB^2+AC^2\) ( ĐL Pytago )

Vì \(\frac{AB}{AC}=\frac{8}{15}\Leftrightarrow\frac{AB}{8}=\frac{AC}{15}\Leftrightarrow\frac{AB^2}{8^2}=\frac{AC^2}{15^2}\). Áp dụng t/c dãy tỉ số bằng nhau

Ta có : \(\frac{AB^2}{8^2}=\frac{AC^2}{15^2}=\frac{AB^2+AC^2}{8^2+15^2}=\frac{BC^2}{64+225}=\frac{2061}{289}=9\)

\(\frac{AB^2}{8^2}=9\Leftrightarrow\sqrt{\frac{AB^2}{8^2}}=\sqrt{9}\Leftrightarrow\frac{AB}{8}=3\Leftrightarrow AB=3.8=24\left(cm\right)\)

\(\frac{AC^2}{15^2}=9\Leftrightarrow\sqrt{\frac{AC^2}{15^2}}=\sqrt{9}\Leftrightarrow\frac{AC}{15}=3\Leftrightarrow AC=15.3=45\left(cm\right)\)

Chu vi \(\Delta ABC=24+45+51=120\left(cm\right)\)

Diện tích \(\Delta ABC=\frac{a\times h}{2}=\frac{24\times45}{2}=\frac{1080}{2}=540\left(cm\right)\)