:v?

bài??????

v

Part 1

1 on

2 as

3 who

4 so

5 well

6 didn't

Part 2

1 - G

2 - A

3 - F

4 - B

5 - C

6 - D

Part 3 

1 have walked

2 learnt

3 watches

4 playing

5 be done

6 impressed

7 surprisingly

8 cosumption

Part4

1 reduce => reduces

2 whom => who

part 1

1 ON

2WHOM

3 WHO

4 SO

5 WELL

6 DIDM'T

part 3

1 walk

2 learnt

3 playing

4 impressive

5 suprising

Part 1:

1. with

2. does

3. after

4. if

5. where

6. I won't

Part 2:

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

Part 3:

1. invited

2. will play

3. have just won

4. be cleaned

5. to take

6. beautifully

7. impression

Part 4:

1. read -> reading

2. disappointing -> disappointed

3. environment -> environmental

4. who -> that

Part 5:

1. the bad weather

2. are made to study

3. were good at learning

4. going to the English

Để hệ phương trình có nghiệm duy nhất thì \(\dfrac{m}{3}< >-\dfrac{1}{m}\)

=>\(m^2\ne-3\)(luôn đúng)

Ta có: \(\left\{{}\begin{matrix}mx-y=2\\3x+my=3m\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=mx-2\\3x+m\left(mx-2\right)=3m\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=mx-2\\3x+m^2x-2m=3m\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=mx-2\\x\left(m^2+3\right)=5m\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{5m}{m^2+3}\\y=m\cdot\dfrac{5m}{m^2+3}-2\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x=\dfrac{5m}{m^2+3}\\y=\dfrac{5m^2-2m^2-6}{m^2+3}=\dfrac{3m^2-6}{m^2+3}\end{matrix}\right.\)

\(\left(x+y\right)\cdot\left(m^2+3\right)+8=0\)

=>\(\dfrac{5m+3m^2-6}{m^2+3}\cdot\left(m^2+3\right)+8=0\)

=>\(3m^2+5m-6+8=0\)

=>\(3m^2+5m+2=0\)

=>(m+1)(3m+2)=0

=>\(\left[{}\begin{matrix}m=-1\\m=-\dfrac{2}{3}\end{matrix}\right.\)

Bài 2:

Thay x=-1 vào (P), ta được:

\(y=\left(-1\right)^2=1\)

Thay x=2 vào (P), ta được:

\(y=2^2=4\)

vậy: A(-1;1); B(2;4)

Gọi (d): y=ax+b(a\(\ne\)0) là phương trình đường thẳng AB

Thay x=-1 và y=1 vào (d), ta được:

\(a\cdot\left(-1\right)+b=1\)

=>-a+b=1(1)

Thay x=2 và y=4 vào (d), ta được:

\(2\cdot a+b=4\)

=>2a+b=4(2)

Từ (1) và (2) ta có hệ phương trình: \(\left\{{}\begin{matrix}-a+b=1\\2a+b=4\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}-3a=-3\\-a+b=1\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}a=1\\b=a+1=1+1=2\end{matrix}\right.\)

Vậy: phương trình AB là y=x+2

Part 1 : 

1. so 

2. forward

3. which

4.didn't

5. if

6. although

Part 2 : 

1.C

2.E

3.A

4.F

5.B

6.D

Part 3 : 

1. eruption

2.compelling

3.badly

4.natural 

5. not to stay 

6. didn't work / has had

8. would tell

Part 4 : 

1. didn't => haven't

2. happily => happy

3. complains => should complain

4. on => off

Câu 5:

Áp dụng bất đẳng thức AM - GM ta có: \(\dfrac{P}{1152}=\dfrac{\sqrt{a-1}}{a}+\dfrac{\sqrt{b-9}}{b}+\dfrac{\sqrt{c-16}}{c}=\dfrac{\sqrt{a-1}}{\left(a-1\right)+1}+\dfrac{\sqrt{b-9}}{\left(b-9\right)+9}+\dfrac{\sqrt{c-16}}{\left(c-16\right)+16}\le\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{8}=\dfrac{19}{24}\Rightarrow P\le912\).

Đẳng thức xảy ra khi a = 2, b = 18, c = 32.

Vậy...