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Mấy câu này dễ mà

a)x thuộc -9;-1

b)x thuộc -15;15

=>bạn phá trị r giải 2 trường hợp

a) |x+5| + 3 = 7

--> |x+5| = 7-3

--> |x+5| = 4

--> x+5=4 hoặc x+5= -4

+ Nếu: x+5=4 + Nếu: x+5= -4

--> x= 4-5 --> x= -4-5

--> x= -1 --> x= -9

Vậy x= -1 hoặc x= -9.

b) 25-|x| = 10

--> |x| = 25-10

--> |x| = 15

--> x=15 hoặc x= -15

Vậy x=15 hoặc x= -15

Chúc bạn học tốt!

a, 5 . 4^x = 80

4^x = 80 : 5

4^x = 16

4^x = 4²

Vậy x = 2

b. 15 - |x| = 25

|x| = 15 - 25

|x| = -10

=> x rỗng vì giá trị tuyệt đối của một số phải là số nguyên dương

c. x² - [6² - (8² - 9 . 7)³ - 7 . 5]³ - 5 . 3 = 1³

   x² - [36 - (64 - 63)³ - 35]³ - 15 = 1

   x² - [36 - 1³ - 35]³ - 15 = 1

   x² - [36 - 1 - 35]³ - 15 = 1

   x² - 0³ - 15 = 1

   x² - 0 - 15 = 1

   x² - 0 = 1 + 15

   x² - 0 = 16

   x² = 16 + 0

   x² = 16

   x² = 4²

Vậy x = 4

d. (x - 7)³ = 2⁵ . 5² + 2 . 10²

    (x - 7)³ = 32 . 25 + 2 . 100

    (x - 7)³ = 800 + 200

    (x - 7)³ = 1000

    (x - 7)³ = 10³

    x - 7 = 10

         x = 10 + 7

         x = 17

Vậy x = 17

b 15-|x|=25 

|x|=15-25 

|x|=-10 

Suy ra x=-10 hoặc x=10

x^2-[6^2-(8^2-9.7)^3-7.5]^3-5.3=1^3 

x^2[36-(64-63)^3-7.5]^3-5.3=1 

x^2[36-1^3-7.5]^3-5.3=1 

x^2[36-1-35]^3-5.3=1 

x^2[35-35]^3-5.3=1 

x^2.0^3-5.3=1

x^2.0-15=1 

x^2.0=1+15 

x^2.0=16 

x^2=16:0 

x^2=16 

=>x=4

1...................How can I help you ?

a. Do you need any help ?

b, How may I help you

c. Let me help you

d. could you help me

2. Let me help you ?-.....................

a, no problem

b. no. thank you

c. thank you, I don't need

d. sure

3. I need a favor.-...................

a. no problem

b. what do you need

c. Yes. I know

d. No thank you

4. .............?- Certainly

a. do you help me ?

b. you don't mind helping me

c. can you help me

d. that's very kind of you

5. .................?- Yes. That's very kind of you

a. may I help you

b. Did you need any help

6. The red bicycle is not as expensive ...............the blue one

a. so

b. like

c. more

d. as

7. They're offering a 10%...........on all sofas this month

a. reward

b. discount

c. reduce

d. cut

8. Mr Brown is the same age............my father

a, as

b. like

c. from

d. with

9. Could you do me a favor, please ?

a, I can't help you

b, Sure. What can I do for you

c. Yes. Thank you

d. Luckily, I am really busy

10. Excuse me! I'm doing my homework,................turn down your radio a bit ?

a, would you like

b. why don't you

c. could you

d. would you mind

11. would you like to see a film?

a, yes I like

b. yes I do

c. Yes I will

d. Great!Let's go

1.d

2.c

3.b

4.c

5.a

6.d

7.b

8.a

9.b

10.c

11.d

\(\dfrac{x^2-3xy+y^2}{x+y+2}=\dfrac{\left(3+\sqrt{5}\right)^2+3\left(3+\sqrt{5}\right)\left(3-\sqrt{5}\right)+\left(3-\sqrt{5}\right)^2}{3+\sqrt{5}+3-\sqrt{5}+2}=\dfrac{9+2\cdot3\sqrt{5}+5+3\left(9-5\right)+9-2\cdot3\cdot\sqrt{5}+5}{8}=\dfrac{40}{8}=5\)

Ta có : \(\frac{6}{11}x=\frac{9}{2}y\)=> \(\frac{12x}{22}=\frac{99y}{22}\)=> 12x = 99y => 4x = 33y => \(\frac{x}{33}=\frac{y}{4}\)

\(\frac{9}{2}y=\frac{15}{5}z\)=> \(\frac{45y}{10}=\frac{30z}{10}\)=> 45y = 30z => 3y = 2z => \(\frac{y}{2}=\frac{z}{3}\)

=> \(\frac{x}{33}=\frac{y}{4};\frac{y}{2}=\frac{z}{3}\)

=> \(\frac{x}{66}=\frac{y}{4};\frac{y}{4}=\frac{z}{12}\)

=> \(\frac{x}{66}=\frac{y}{4}=\frac{z}{12}\)và y - x + z = -120

Áp dụng t/c dãy tỉ số bằng nhau ta có :

\(\frac{x}{66}=\frac{y}{4}=\frac{z}{12}=\frac{y-x+z}{4-66+12}=\frac{-120}{-50}=\frac{12}{5}\)

=> \(\hept{\begin{cases}\frac{x}{66}=\frac{12}{5}\\\frac{y}{4}=\frac{12}{5}\\\frac{z}{12}=\frac{12}{5}\end{cases}}\)=> \(\hept{\begin{cases}x=\frac{792}{5}\\y=\frac{48}{5}\\z=\frac{144}{5}\end{cases}}\)

Hãy sắp xếp những câu sau thành hai bài hội thoại hợp lí:

P1

(1)Could you do me a favor, please?

(2)Sure. What can i do for you?

(3)Yes. Could you show me to the nearest bus-stop?

(4)Certainly. Go ahead. Take the second turning on the left. It's on the way.

(5)Thank you. i'm sure i'll find it.

P2

(1)Do you need my help?

(2)Can you help me remove this motorbike? It's on the way.

(3)No problem. i'll help you.

(4)Thank you very much. That's very kind of you.