\(2x^2+100x-10000=0\)

\(\Leftrightarrow2x^2+200x-100x-10000=0\)

\(\Leftrightarrow2x\left(x+100\right)-100\left(x+100\right)=0\)

\(\Leftrightarrow\left(2x-100\right)\left(x+100\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}2x-100=0\\x+100=0\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=50\\x=-100\end{cases}}\)

\(\frac{2}{b}=\frac{1}{a}+\frac{1}{c}\Rightarrow b=\frac{2ac}{a+c}\)

ta có: \(P=\frac{a+\frac{2ac}{a+c}}{2a-\frac{2ac}{a+c}}+\frac{c+\frac{2ac}{a+c}}{2c-\frac{2ac}{a+c}}=\frac{\frac{a^2+3ac}{a+c}}{\frac{2a^2}{a+c}}+\frac{\frac{c^2+3ac}{a+c}}{\frac{2c^2}{a+c}}\)

\(=\frac{a^2+3ac}{2a^2}+\frac{c^2+3ac}{2c^2}=1+\frac{3}{2}\left(\frac{c}{a}+\frac{a}{c}\right)\ge1+\frac{3}{2}\cdot2\sqrt{\frac{c}{a}\cdot\frac{a}{c}}=4\)

Dấu "=" xảy ra khi a=b=c

Đổi 20 phút =1/3h

Gọi vận tốc xe 1 là x( km ) ĐK: x>5

nên vận tốc xe 2 là x-5 (km)

Thời gian mà xe 1 đi từ A đến B là \(\frac{150}{x}\left(h\right)\)

Thời gian mà xe 2 đi từ A đến B là \(\frac{150}{x-5}\left(h\right)\)

Ta có pt sau\(\frac{150}{x-5}-\frac{105}{x}=\frac{1}{3}\)

Làm nốt nhé bạn mình đang vội

When you ride a bicycle, motorised foot scooter or a personal mobility device a segway, you must wear an Australian Standard (AS) approved bicycle helmet. You must securely fit and fasten it. An approved bicycle helmet means a helmet that complies with AS 2063 or AS/NZS 2063.

You may only carry passengers on your bicycle if the bicycle is designed to carry passengers. If you carry a passenger on your bicycle, they must also wear an approved helmet, securely fitted and fastened. However, if they are a paying passenger on a 3 or 4 wheeled bicycle, they do not have to wear a helmet.

You do not need to wear a helmet if you have a doctor's certificate stating that, for a specific amount of time, you cannot wear a helmet:

• for medical reasons
• because of a physical characteris that makes it unreasonable for you to wear one.

If you have a doctor's certificate, you must carry it with you when you ride without a helmet.

You also do not need to wear a helmet if you are a member of a religious group and are wearing a headdress customarily worn by your group, that makes it impracal to wear a helmet.

Attaching a camera

There is no law that prohibits the attachment of a camera to a bicycle helmet, as long as the helmet remains compliant with the above mentioned standards, and is an approved attachment (according to the helmet manufacturer).

You may use a camera mounted on your bicycle or a body mounted camera as an alternative.

Bicycle equipment

Every time you ride, your bicycle must have:

• at least 1 working brake
• a working bell, horn or a similar warning device.

Bicycle equipment for night time and unsafe weather

If you ride at night or in weather conditions that make it difficult to see, you must display (either on the bicycle or on you):

• a white light (flashing or steady) that can be clearly seen at least 200m from the front of the bicycle
• a red light (flashing or steady) that can be clearly seen at least 200m from the back of the bicycle
• a red reflector that can be clearly seen at least 50m from behind the bicycle—when a vehicle's headlights shine on it.

When you ride a bicycle, motorised foot scooter or a personal mobility device a segway, you must wear an Australian Standard (AS) approved bicycle helmet. You must securely fit and fasten it. An approved bicycle helmet means a helmet that complies with AS 2063 or AS/NZS 2063.

You may only carry passengers on your bicycle if the bicycle is designed to carry passengers. If you carry a passenger on your bicycle, they must also wear an approved helmet, securely fitted and fastened. However, if they are a paying passenger on a 3 or 4 wheeled bicycle, they do not have to wear a helmet.

You do not need to wear a helmet if you have a doctor's certificate stating that, for a specific amount of time, you cannot wear a helmet:

for medical reasons
because of a physical characteris that makes it unreasonable for you to wear one.
If you have a doctor's certificate, you must carry it with you when you ride without a helmet.

You also do not need to wear a helmet if you are a member of a religious group and are wearing a headdress customarily worn by your group, that makes it impracal to wear a helmet.

Attaching a camera

There is no law that prohibits the attachment of a camera to a bicycle helmet, as long as the helmet remains compliant with the above mentioned standards, and is an approved attachment (according to the helmet manufacturer).

You may use a camera mounted on your bicycle or a body mounted camera as an alternative.

Bicycle equipment
Every time you ride, your bicycle must have:

at least 1 working brake
a working bell, horn or a similar warning device.
Bicycle equipment for night time and unsafe weather
If you ride at night or in weather conditions that make it difficult to see, you must display (either on the bicycle or on you):

a white light (flashing or steady) that can be clearly seen at least 200m from the front of the bicycle
a red light (flashing or steady) that can be clearly seen at least 200m from the back of the bicycle
a red reflector that can be clearly seen at least 50m from behind the bicycle—when a vehicle's headlights shine on it.

a) 3x(x - 1) + 2(x - 1) = 0

<=> (3x + 2)(x - 1) = 0

<=> \(\orbr{\begin{cases}3x+2=0\\x-1=0\end{cases}}\)

<=> \(\orbr{\begin{cases}x=-\frac{2}{3}\\x=1\end{cases}}\)

Vậy S = {-2/3; 1}

b) x² - 1 - (x + 5)(2 - x) = 0

<=> x² - 1 - 2x + x² - 10 + 5x = 0

<=> 2x² + 3x - 11 = 0

<=> 2(x² + 3/2x + 9/16 - 97/16) = 0

<=> (x + 3/4)² - 97/16 = 0

<=> \(\orbr{\begin{cases}x+\frac{3}{4}=\frac{\sqrt{97}}{4}\\x+\frac{3}{4}=-\frac{\sqrt{97}}{4}\end{cases}}\)

<=> \(\orbr{\begin{cases}x=\frac{\sqrt{97}-3}{4}\\x=-\frac{\sqrt{97}-3}{4}\end{cases}}\)

Vậy S = {\(\frac{\sqrt{97}-3}{4}\); \(-\frac{\sqrt{97}-3}{4}\)

d) x(2x - 3) - 4x + 6 = 0

<=> x(2x - 3) - 2(2x - 3) = 0

<=> (x - 2)(2x - 3) = 0

<=> \(\orbr{\begin{cases}x-2=0\\2x-3=0\end{cases}}\)

<=> \(\orbr{\begin{cases}x=2\\x=\frac{3}{2}\end{cases}}\)

Vậy  S = {2; 3/2}

e)  x³ - 1 = x(x - 1)

<=> (x - 1)(x² + x + 1) - x(x - 1) = 0

<=> (x - 1)(x² + x +  1 - x) = 0

<=> (x - 1)(x² + 1) = 0

<=> x - 1 = 0

<=> x = 1

Vậy S = {1}

f) (2x - 5)² - x² - 4x - 4 = 0

<=> (2x - 5)² - (x + 2)² = 0

<=> (2x - 5 - x - 2)(2x - 5 + x + 2) = 0

<=> (x - 7)(3x - 3) = 0

<=> \(\orbr{\begin{cases}x-7=0\\3x-3=0\end{cases}}\)

<=> \(\orbr{\begin{cases}x=7\\x=1\end{cases}}\)

Vậy S = {7; 1}

h) (x - 2)(x² + 3x - 2) - x³ + 8 = 0

<=> (x - 2)(x² + 3x - 2) - (x- 2)(x² + 2x + 4) = 0

<=> (x - 2)(x² + 3x - 2 - x² - 2x - 4) = 0

<=> (x - 2)(x - 6) = 0

<=> \(\orbr{\begin{cases}x-2=0\\x-6=0\end{cases}}\)

<=> \(\orbr{\begin{cases}x=2\\x=6\end{cases}}\)

Vậy S = {2; 6}

\(a,3x\left(x-1\right)+2\left(x-1\right)=0\)

\(3x.x-3x+2x-2=0\)

\(2x-2=0\)

\(2x=2\)

\(x=1\)

https://diendan.hocmai.vn/threads/sao-minh-hoc-te-he-3-an-wa.231539/

tham khảo nha. mình lười viết

1. Chép ba câu thơ 

Lướt giữa mây cao với biển bằng,
Ra đậu dặm xa dò bụng biển,
Dàn đan thế trận lưới vây giăng

Đoạn thơ là hành trành đoàn thuyền đánh cá ra khơi.

2. Biện pháp phóng đại của cảm hứng lãng mạn đã thổi một nguồn sinh lực lớn vào các hình ảnh, biến cái bình thường thành cái khác thường, tạo nên hiệu quả thẩm mĩ thú vị. Hai động từ “lái”, “lướt” đã kết nối các hình ảnh thành một không gian vũ trụ đặc biệt: con thuyền nhỏ bé bỗng được nâng lên tầm vóc thật lớn lao khi nó được đặt trong tương quan với bốn hình ảnh kì vĩ: gió, trăng, mây cao, biển bằng. Con thuyền ở giữa, làm chủ tất cả, lấy gió làm lái, lấy trăng làm buồm, lấy mây cao, biển bằng làm không gian lướt sóng. Con thuyền chính là con người, con người mang tầm vóc vũ trụ, làm chủ vũ trụ và cuộc đời.

3. Yêu cầu:

- Hình thức: đoạn văn khoảng nửa trang giấy

- Nội dung: Suy nghĩ về hình ảnh ngư dân ngày đêm ra khơi bám biển.