K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

IChoose the best answer to complete the passage:Milk is produced ( 1 )farms from cows.Firstly, the cows are milked. This (2) happens twice aday, using a milk machine. Then, the milk is cooled and stored in large, refrigerated containers. Next,the milk is collected and delivered to the dairy. (3), at the diary, milk is made into various products(4) cheese, cream, butter and liquid milk for drinking. Finally, these are (5) to supermarkets andshops.1. A. in                                B. at   ...
Đọc tiếp

IChoose the best answer to complete the passage:
Milk is produced ( 1 )farms from cows.Firstly, the cows are milked. This (2) happens twice a
day, using a milk machine. Then, the milk is cooled and stored in large, refrigerated containers. Next,
the milk is collected and delivered to the dairy. (3), at the diary, milk is made into various products
(4) cheese, cream, butter and liquid milk for drinking. Finally, these are (5) to supermarkets and
shops.
1. A. in                                B. at                               C. on                        D. by
2. A. lately                           B. usually                      C. recently                D. finally
3. A. Although                     B. After that                   C. However               D. Finally
4. A. including                     B. included                    C. such as                 D. A and C
5. A. deliver                        B. delivering                    C. delivered             D. delivery

II/ Read the following passage and choose the best answer each of the questions.
Coca- Cola is enjoyed all over the world. 1.6 billion gallons are sold every year, in over one
hundred and sixty countries. The drink was invented by Dr John Pemberton in Atlanta, on 8 May
1886, but it was given the name Coca-Cola by his partner, Frank Robinson. In the first year, only nine
drinks a day were sold. The business was bought by a man called Asa Candler in 1888, and the first
factory was opened in Dallas, Texas, in 1895. Coca- Cola is still made there. Billions of bottles and
cans have been produced since 1895.
1. The one who invented Coca Cola was ..................
A. Dr John Pemberton                   B. Frank Robinson
C. Asa Candler                               D. Dallas

2. What does the word “it” in line 3 refer to?
A. the world B. gallon C. country D. the drink
3. The first Coca Cola company was opened...................
A. in 1886 B. in 1888 C. in 1895 D. since 1895
4. Nowadays, Coca Cola is sold ........................
A. all over the world          B. in more than 160 countries
C. everywhere                   D. all are correct

5. Which of the following is not true?
A. Every year, 1.6 billion gallons of Coca Cola are sold.
B. Coca- Cola is still produced in Dallas.
C. Nowadays, people don’t want to buy Coca – Cola any more.
D. At first, people didn’t like Coca- Cola very much.

0

\(3x^2+50x-800=0\Leftrightarrow3\left(x^2+\frac{50}{3}x-\frac{800}{3}\right)=0\)

\(\Leftrightarrow3\left(x^2-10x+\frac{80}{3}x-\frac{800}{3}\right)=0\Leftrightarrow3\left(x-10\right)\left(x+\frac{80}{3}\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=10\\x=-\frac{80}{3}\end{cases}}\).Vậy \(S=\left\{10,-\frac{80}{3}\right\}\)

26 tháng 2 2020

Nhẩm thấy có nghiệm x=10

Phân tích VT thành nhân tử: \(3x^2+50x-800=\left(3x+80\right)\left(x-10\right)\)=0

\(\Leftrightarrow\orbr{\begin{cases}3x+80=0\\x-10=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{-80}{3}\\x=10\end{cases}}}\)

Vậy phương trình có hai nghiệm như trên.

26 tháng 2 2020

Bài  3: Khai triển: 

\(\text{a) (x + 5)2 =2x+10}\)

\(\text{b) (x – 3y)2 =2x-6y}\)

\(\text{c) (x2 – 6z)(x2 + 6z)=}4x^2-36z^2\)

26 tháng 2 2020

Mấy cái số 2 là bình phương hả bạn

26 tháng 2 2020

a,2x(x + 2)2 – 8x2 = 2(x – 2)(x2 + 2x + 4)

<=>  2x(x^2  + 4x + 4) - 8x^2 = (2x - 4)(x^2 + 2x + 4)

<=>  2x^3 + 8x^2 + 8x - 8x^2 = 2x^3 + 4x^2 + 8x - 4x^2 - 8x - 16

<=>  2x^3 + 8x = 2x^3  - 16

<=>  8x = -16

<=>  x = -2

b,(x – 2)3 + (3x – 1)(3x + 1) = (x + 1) 

<=>  x^3 - 3.x^2.2 + 3.x.2^2 - 8 + 9x^2 - 1 = x^3 + 3.x^2.1 + 3.x.1^2 + 1

<=>  x^3 - 6x^2 + 12x - 8 + 9x^2 - 1 = x^3 +  3x^2 + 3x + 1

<=>  x^3 + 3x^2 + 12x - 9 = x^3 + 3x^2 + 3x + 1

<=>  12x - 9 = 3x + 1

<=>  12x - 3x = 1 + 9

<=>  9x = 10

<=>  x = 10/9

26 tháng 2 2020

c) \(\left(x+1\right)\left(2x-3\right)=\left(2x-1\right)\left(x+5\right)\)

\(\Leftrightarrow2x^2-x-3=2x^2+9x-5\)

\(\Leftrightarrow10x-2=0\)

\(\Leftrightarrow x=\frac{1}{5}\)

Vậy tập nghiệm của phương trình là \(S=\left\{\frac{1}{5}\right\}\)

d) \(\left(x-1\right)^3-x\left(x+1\right)^2=5x\left(2-x\right)-11\left(x+2\right)\)

\(\Leftrightarrow x^3-3x^2+3x-1-x^3-2x^2-x=10x-5x^2-11x-22\)

\(\Leftrightarrow-5x^2+2x-1=-5x^2-x-22\)

\(\Leftrightarrow3x+21=0\)

\(\Leftrightarrow x=-7\)

Vậy tập nghiệm của phương trình là \(S=\left\{-7\right\}\)

26 tháng 2 2020

\(\text{a) 7-2x=22-9x}\)

\(\Leftrightarrow\text{7-2x-22+9x=0}\)

\(\Leftrightarrow-15+7x=0\)

\(\Leftrightarrow7x=15\)

\(\Leftrightarrow x=\frac{15}{7}\)

Học tốt

#Thảo Vy#

26 tháng 2 2020

\(\text{b) x-12+4x=25+2x-1}\)

\(\Leftrightarrow x-12+4x-25-2x+1=0\)

\(\Leftrightarrow3x-36=0\)

\(\Leftrightarrow x=\frac{36}{3}=12\)

Vậy..

Học tốt

#Thảo Vy#

26 tháng 2 2020

a)\(x^2+x-x^2+2=0\)\(\Rightarrow x+2=0\)\(\Rightarrow x=-2\)

b)\(2\left(3x+2\right)-2\left(x+6\right)=0\)

\(\Rightarrow2\left(3x+2-x-6\right)=0\)

\(\Rightarrow2\left(2x-4\right)=0\)

\(\Rightarrow2x-4=0\Rightarrow x=2\)

c)\(4x^4-6x^3-4x^4+6x^3-2x^2=0\)

\(\Rightarrow-2x^2=0\Rightarrow x=0\)

d)\(\left(3x^2-x-2\right)-3\left(x^2-x-2\right)=4\)

\(\Rightarrow3x^2-x-2-3x^2+3x+6=4\)

\(\Rightarrow2x+4=4\Rightarrow2x=0\Rightarrow x=0\)

25 tháng 4 2021
Looooooooo
26 tháng 2 2020

\(x^2-x+y^2-y=\frac{1}{2}\)

\(\Leftrightarrow\left(x^2+y^2\right)-\left(x+y\right)=\frac{1}{2}\)

\(\Leftrightarrow\left(x+y\right)\left(x-y\right)-\left(x+y\right)=\frac{1}{2}\)

\(\Leftrightarrow\left(x+y\right)\left(x-y-1\right)=\frac{1}{2}\)

\(\Leftrightarrow\left(x+y\right)=\frac{1}{2}\)Hoặc \(\Leftrightarrow x-y-1=\frac{1}{2}\)

giải đến đây tui cứ thấy sao sao í ko bt do tui lm sai hay sao

26 tháng 2 2020

Độ dài cạnh AB là: 3,5 + 14 = 17,5 (cm)

Tỉ số từ điểm B đến cạnh AB là:

3,5 : 17,5 = 1/5 (AB)

Tỉ số từ điểm D đến cạnh AB là:

14 : 17,5 = 4/5 (AB)

\(a,4x^2-\left(2x-1\right)\left(1-4x\right)=1\)

\(\left(2x-1\right)\left(1-4x\right)=4x.4x-1\)

\(TH1:\orbr{\begin{cases}2x-1=4x.4x-1\\1-4x=4x.4x-1\end{cases}}\Rightarrow\orbr{\begin{cases}2x-4x.4x=-1+1\\-4x-4x.4x=-1-1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}2x-16x=0\\-4x-16x=-2\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}-14x=0\\-20x=-2\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=\frac{1}{10}\end{cases}}}\)

Vậy pt có nghiệm là (x;y) = (0;1/10) 

tự thực hiện tiếp vs dấu - , kl TH1 thoi