\(x^2+\sqrt{5}x-10=0\)

\(\Delta=5-4\left(-10\right)=45>0\)

Vậy pt có nghiệm pb 

\(x_1=\dfrac{-\sqrt{5}-3\sqrt{5}}{2}=-2\sqrt{5};x_2=\dfrac{-\sqrt{5}+3\sqrt{5}}{2}=\sqrt{5}\)

\(5,=\dfrac{2^3\cdot3^3\cdot2^5\cdot3^7}{2^8\cdot3^9}=3\\ 6,2^{50}+2^{49}-2^{48}=2^{46}\left(2^4+2^3-2^2\right)=2^{46}\cdot20⋮5\left(20⋮5\right)\)

a

A

A

Chọn trọng âm khác:

1. A. explain      B. involve       C. borrow       D. discuss

2. A. behave      B. relax        C. enter       D. allow

3. A. disaster        B. origin       C. charity       D. agency

4. A. president        B. opponent        C. assistant        D. companion

5. A. obtain        B. perform        C. affect        D. happen

6. A. successful       B. important        C. musical        D. expensive 

7. A. arrive        B. accept        C. include        D. practice

8. A. beauty       B. album       C. question       D. success

9. A. imagine      B. discover       C. decorate       D. consider

Chọn đáp án đúng:

1. Why did you have to...me...in front of everybody like that?

A. put-off       B. put-down       C. put-at         D. put-by

2. If you don't want to catch a train home at that time of night, you're welcome to....

A. sleep with      B. sleep over       C. sleep in       D. sleep on

Chọn trọng âm khác:

1. A. explain      B. involve       C. borrow       D. discuss

2. A. behave      B. relax        C. enter       D. allow

3. A. disaster        B. origin       C. charity       D. agency

4. A. president        B. opponent        C. assistant        D. companion

5. A. obtain        B. perform        C. affect        D. happen

6. A. successful       B. important        C. musical        D. expensive 

7. A. arrive        B. accept        C. include        D. practice

8. A. beauty       B. album       C. question       D. success

9. A. imagine      B. discover       C. decorate       D. consider

Chọn đáp án đúng:

1. Why did you have to...me...in front of everybody like that?

A. put-off       B. put-down       C. put-at         D. put-by

2. If you don't want to catch a train home at that time of night, you're welcome to....

A. sleep with      B. sleep over       C. sleep in       D. sleep on

Bài 2:

a) \(\dfrac{2}{15}-\dfrac{7}{10}=\dfrac{4}{30}-\dfrac{21}{30}=-\dfrac{17}{30}\)

b) \(\dfrac{-3}{14}+\dfrac{2}{21}=\dfrac{-9}{42}+\dfrac{4}{42}=\dfrac{-5}{42}\)

c) \(\dfrac{-6}{9}+\dfrac{-12}{16}=\dfrac{-96}{144}+\dfrac{-108}{144}=\dfrac{-204}{144}=-\dfrac{17}{12}\)

Bài 3: 

a) \(\dfrac{3}{8}+\dfrac{-5}{6}=\dfrac{3}{8}-\dfrac{5}{6}=\dfrac{18}{48}-\dfrac{40}{48}=-\dfrac{22}{48}=-\dfrac{11}{24}\)

b) \(\dfrac{-8}{18}-\dfrac{15}{27}=\dfrac{-24}{54}-\dfrac{30}{54}=\dfrac{-54}{54}=-1\)

c) \(\dfrac{2}{21}-\dfrac{-1}{28}=\dfrac{8}{84}-\dfrac{-3}{84}=\dfrac{11}{84}\)

part 7 Using the suggested words to write a story

1 It/be/beautiful day.Sun/shine

-> It was a beautiful day. The Sun was shining.

2.Nga/outside/play/her dog.All of sudden,the dog/behave strangely

-> Nga was outside playing with her dog. All of sudden, the dog was behaving strangly.

3.Nga/run/home/with/the dog/tell/mother/what her dog/doing

-> Nga ran home with the dog to tell her mother what her dog was doing.

4.Nga's mother/tell Nga/she/hear/on TV/there/be/a typhoon coming

-> Nga's mother told Nga she heard on TV that there was a typhoon coming. 

1 It/be/beautiful day.Sun/shine

-> It was a beautiful day. The Sun was shining.

2.Nga/outside/play/her dog.All of sudden,the dog/behave strangely

-> Nga was outside playing with her dog. All of sudden, the dog behaved strangly.

3.Nga/run/home/with/the dog/tell/mother/what her dog/doing

-> Nga ran home with the dog to tell her mother what her dog was doing.

4.Nga's mother/tell Nga/she/hear/on TV/there/be/a typhoon coming

-> Nga's mother told Nga she heard on TV that there was a typhoon coming. 

Bạn xem lại, làm gì có cái ảnh đề nào đâu?

a: \(\Leftrightarrow2x\left(x+2\right)+4>x^2+4x+4\)

\(\Leftrightarrow2x^2+4x-x^2-4x>0\)

=>x<>0

b: \(\Leftrightarrow3\left(1-2x\right)-24x< 4\left(1-5x\right)\)

=>3-6x-24x<4-20x

=>-30x+3<4-20x

=>-10x<1

hay x>-1/10

c: \(\Leftrightarrow x^2+6x+8>x^2+10x+16+26\)

=>6x+8>10x+42

=>-4x>34

hay x<-17/2

ko bit gui

S=−(a−b−c)+(−c+b+a)−(a+b)

S=−a+b+c−c+b+a−a−b

S=(−a+a−a)+(b+b−b)+(c−c)

S=−a+b

Cảm ơn '' Nguyễn Đức Mạnh '' nhiều nha