\(\Leftrightarrow\sqrt{x+4}\left(\sqrt{x-4}-2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+4=0\\x-4=4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-4\\x=8\end{matrix}\right.\)

a, ĐKXĐ: \(x\le2\)

\(\sqrt{4-2x}=5\\ \Leftrightarrow4-2x=25\\ \Leftrightarrow2x=-21\\ \Leftrightarrow x=-10,5\left(tm\right)\)

b, ĐKXĐ: \(x\ge-1\)

\(\sqrt{25\left(x+1\right)}+\sqrt{9x+9}=16\\ \Leftrightarrow5\sqrt{x+1}+\sqrt{9\left(x+1\right)}=16\\ \Leftrightarrow5\sqrt{x+1}+3\sqrt{x+1}=16\\ \Leftrightarrow8\sqrt{x+1}=16\\ \Leftrightarrow\sqrt{x+1}=2\\ \Leftrightarrow x+1=4\\ \Leftrightarrow x=3\)

c, \(\sqrt{4x^2+12x+9}=4\Leftrightarrow4x^2+12x+9=16\\ \Leftrightarrow4x^2+12x-7=0\\ \Leftrightarrow\left(4x^2-2x\right)+\left(14x-7\right)=0\\ \Leftrightarrow2x\left(2x-1\right)+7\left(2x-1\right)=0\\ \Leftrightarrow\left(2x-1\right)\left(2x+7\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=-\dfrac{7}{2}\end{matrix}\right.\)

a: \(\Leftrightarrow4-2x=25\)

hay \(x=-\dfrac{21}{2}\)

c: \(\Leftrightarrow\left|2x+3\right|=4\)

\(\Leftrightarrow\left[{}\begin{matrix}2x+3=4\\2x+3=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=-\dfrac{7}{2}\end{matrix}\right.\)

part 1

1 where

2 which

3 important

4 traditional

5 of

6 even though

part 2

1G 2A 3F 4D 5C 6B

part 3

1 not watching

2 would arrive

3 would pay

4 playing

5 has worked

6 harmed

7 unsuccessful

 8 richly

part 4

1 internation -> international

2 write -> be written

part 5

1 have to be taken

2 spends 2 hours doing

3 unless someone puts

4 which I visited 

part 6

1 natural

2 economically

3 resources

4 before

part 7

1T 2T 3F 4T

Part 1

1 friendliness

2 were

3 after

4 written

5 correspond

6 which

Part2

1 - D

2 - C

3 - A

4 - G

5 - E

6 - F

Part 3

1 should do

2 visiting

3 cut

4 made

5 has learnt

6 modernize

7commercial

8 untreated

Part 4

1 will => would

2 carefully => careful

Part 5

1 I would pay a visit to 

2 planted trees along the

3 going to be sent

4 which I borrowed from

Part 6

1 subtances

2 Industrial

3 frequently

4 that

Part 1

1 friendliness

2 were 

3 after

4 written

5 correspond

6 which

Part 2

1D 2C 3A 4G 5E 6F

Part3

1 have to do

2 visiting

3 cut

4 was making

5 has learnt

6 modernize

7 commercially

8 mistreated

Part 4

1 will -> would

2 carefully -> careful

Part 5

1 to pay a visit

2 planted trees along the

3 going to be sent 

4 that I borrowed from

Part 6

1 substances

2 industrial

3 naturally

4 that 

Part 7

1F 2F 3T 4T

1, C=> visited

2, B=> the last bus

3, D=> between

4, B=> such

5, C=>to see

6, C=>widely

7, D=>in Friday afternoon

8, B=>information

2: Xét ΔABC vuông tại A có 

\(BC^2=AB^2+AC^2\)

hay \(AC=\dfrac{14\sqrt{2}}{5}\left(cm\right)\)

Xét ΔABC vuông tại A có

\(\sin\widehat{C}=\dfrac{41}{57}\)

\(\Leftrightarrow\widehat{C}\simeq46^0\)

hay \(\widehat{B}=44^0\)