IV

1 do 

2 to be

3 was waiting

4 went - wouldn't be

5 were

6 smoking

7 is always leaving

8 to study

9 haven't spoken

10 arrive

V

1 wealthy

2 imagination

3 literately

4 phýical

5 observation

6 Married

7 behavior

8 incredible

9 seniority

10 unbelievable

IV

1 do 

2 to be

3 was waiting

4 went - wouldn't be

5 were

6 smoking

7 is always leaving

8 to study

9 haven't spoken

10 arrive

V

1 wealthy

2 imagination

3 literately

4 physical

5 observation

6 Married

7 behavior

8 incredible

9 seniority

10 unbelievable

Chụp câu hỏi lên mới giúp được chứ e

I wish the council wasn't demolishing it

 If I were good at English, I could become a tour guide

"I will hold an event about skin care next month" Mary said

She was given the book " The fault in our stars " as a birthday gift by him

He wishes he could come to his brother's wedding

He advised me not to longer spend most of time chatting on Facebook.

How long did you start searching for some facts in the past ?

My mother used to for me when I married my wife

She was so frightened that she lost control of her car. 

It was such a delicious dessert that I decided to order portion

Because of my sickness, I don't go out

is=>was

leave=>will leave

since=>for

difficult than=>more difficult than

have been=>had been

 so =>too

endangerment=>endangered 

2: x+13 là bội của x-1

=>\(x+13⋮x-1\)

=>\(x-1+12⋮x-1\)

=>\(x-1\inƯ\left(12\right)\)

mà x-1>=-1(vì x là số tự nhiên)

nên \(x-1\in\left\{-1;1;2;3;4;6;12\right\}\)

=>\(x\in\left\{0;2;3;4;5;7;13\right\}\)

3: 4x+9 là bội của 2x+1

=>\(4x+9⋮2x+1\)

=>\(4x+2+7⋮2x+1\)

=>\(2x+1\in\left\{1;7\right\}\)

=>\(x\in\left\{0;3\right\}\)

bài 2

a) ĐKXĐ: a\(\ge\)0, a\(\ne\)1

b)P=\(\dfrac{1+\sqrt{a}-1+\sqrt{a}}{\left(1-\sqrt{a}\right)\left(1+\sqrt{a}\right)}\).\(\dfrac{1+\sqrt{a}}{\sqrt{a}}\)

P=\(\dfrac{2\sqrt{a}}{\left(1-\sqrt{a}\right)\left(1+\sqrt{a}\right)}.\dfrac{1+\sqrt{a}}{\sqrt{a}}\)

P=\(\dfrac{2}{1-\sqrt{a}}\)

c) thay a=4 vào biểu thức ta có

P=\(\dfrac{2}{1-\sqrt{4}}\)=\(\dfrac{2}{1-2}\)=-2

d) để P=9 thì

\(\dfrac{2}{1-\sqrt{a}}=9\)\(\Rightarrow\)2=9(1-\(\sqrt{a}\))

\(\Rightarrow\)2=9-\(9\sqrt{a}\)\(\Rightarrow\)\(9\sqrt{a}=7\)\(\Rightarrow\)\(\sqrt{a}=\dfrac{7}{9}\)

\(\Rightarrow a=\dfrac{49}{81}\)

bài 3

a) \(\sqrt{9x^2}=4\Rightarrow3x=4\)\(\Rightarrow\)\(x=\dfrac{4}{3}\)

b)\(\Rightarrow\)\(\left(x-\sqrt{5}\right)^2\)=0\(\Rightarrow x-\sqrt{5}=0\)

\(\Rightarrow x=\sqrt{5}\)

a: \(\left\{{}\begin{matrix}3x+6y=4\\x+4y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{1}{3}\\x=\dfrac{2}{3}\end{matrix}\right.\)