\(Q=\left(x^2+x+5\right)\left(5-x^2-x\right)=25-\left(x^2+x\right)^2\le25\)

Dấu = xảy ra khi \(x^2+x=0\Leftrightarrow\orbr{\begin{cases}x=-1\\x=0\end{cases}}\)

=>   \(-Q=\left(x^2+x+5\right)\left(x^2+x-5\right)\)

=>   \(-Q=\left(x^2+x\right)^2-25\)

Có:   \(\left(x^2+x\right)^2\ge0\forall x\)

=>   \(-Q\ge-25\forall x\)

=>     \(Q\le25\)

DẤU "=" XẢY RA <=>   \(\left(x^2+x\right)^2=0\)

<=>   \(x^2+x=0\)

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

VẬY Q MAX = 25 <=>    \(\orbr{\begin{cases}x=0\\x=-1\end{cases}}\)

( x - 3 )² + ( x - 2 )²

= x² - 6x + 9 + x² - 4x + 4

= 2x² - 10x + 13

= 2( x² - 5x + 25/4 ) + 1/2

= 2( x - 5/2 )² + 1/2

\(2\left(x-\frac{5}{2}\right)^2\ge0\forall x\Rightarrow2\left(x-\frac{5}{2}\right)^2+\frac{1}{2}\ge\frac{1}{2}\)

Dấu " = " xảy ra <=> x - 5/2 = 0 => x = 5/2

Vậy GTNN của biểu thức = 1/2 , đạt được khi x = 5/2

Ánh sáng yếu lắm , với cả chữ hơi khó đọc , hay viết tắt , nếu chứ khó đọc thì hãy viết mực xanh nhìn sáng với cả dễ đọc hơn nhiều đó bn .viết lại đi nếu biết mik trả lời cho nha okay !

dễ nhưng ko bit làm

viết lại đi lắn nót vào mới đọc được và hiểu được để mà trả lời chứ viết rõ chữ vào đừng viết tắt

Exercise 2: Fill in the correct forms of adverbs and adjectives
1. Those shoes are (pretty)........prettier than.........................these ones.
2. Marissa is (young)...........younger than.....................I am.
3. Texas is (big)..............bigger than..................Arizona.
4. He is much (old).........older than ...............I expected.
5. During the volleyball game, the mothers seemed to be (energetic).............more energetic.................their daughters.
6. Planes fly (high).........higher than..................birds.
7. Nashla gets to school (early)........earlier than...................her sister Rosemary.
8. Frankie’s pitch this season was (bad).........worse than..................last season’s.
9. Dar. Rani’s office is (far)........farther......................down the block.
10. Apartment’s rentals in Brooklyn are (expensive).............the most expensive....................rentals in The Bronx.

Exercise 3: Put the verbs into correct forms using First or Second conditional sentences
1. If we (rent).............rent.........that big flat, we (have).............will have.........enough room for the dog.
2. I (buy)..........would buy............a huge house with a garden if I (win).............won.........the lottery.
3. If you (paint).........painted.............this room white it (be)..........would be............much lighter.
4. I (do)...........would do...........it myself if I (have).............had.........more time.
5. I (not be).........wouldn't be.............so broke if I (spend)............spent..........so much on going out.
6. Maybe if I (share)...........share...........a flat with friends, I (get on)..............will get on ........better with my parents.
7. I (can).............could.........travel next summer if I (have)........had................more money.
8. Carla (move).......would...............out of her shared flat if she (find)..............found........a job.
9. If my girlfriend (not have to).........didn't have to..........................work so hard, we (can)..............could........see each
other more often.
10. If I (go)..........went............to bed earlier, I (not be).......wouldn't be...............so tired all the time.

Exercise 4: Put the verbs into correct forms using The past simple tense, The past continuous tense or
The present perfect tense
1. My friend’s a great writer. He (write)has written lots of books so far.
2. We (not have)............didn't have.........a holiday last year, because there (not be)..........was not.. enough time for that.
3. The weather (be).......was........very good yesterday so Kelly (not stay)................didn't stay.................at home.
4. My hair is wet. I (just wash)have just washed it.
5. Is Sonia here? No, she (not come)hasn't come yet.
6. Do you know Martin’s sister? I (see)have seen her a few times but I have never spoken to her. Have You (ever speak)..ever spoken.........................to her? Yes, I
(meet)met her at a party last week. She’s very nice.
7. We (travel) have traveled around South America since June and (already
explore).........................have already explored........ an amazing historic site Machu Picchu in Peru.
8. Albert Einstein (be).......was...........the scientist who (develop)......developed..................the theory of relativity.
9. How long have you (use)..........used..............a bike to get around London? I (buy)..........bought..............this 2 weeks ago and I (ride)..........have ridden..............it every day since I got it.
10. My parents (live)..........have lived.......................in London since they (get married)............got married.................in 1975. They still adore this city.

Exercise 9: Write a short paragraph about a future means of transport, using the cues given.

Safe, environmentally friendly cars

1. Cars/ the future/ do less damage/ the environment/ and/ be equipped/ better safety devices/ limit/ number/accidents and deaths.
Cars in the future will do less damage to the environment and will be equipped better safety devices to limit the number of accidents and deaths.
2. Engines/ be powered/ by/ rubbish-fueled reactor/to make use/ all the waste we produce.
Engines will be powered by rubbish-fueled reactor to make use of all the waste we produce.
3. Petrol/ be replaced/ fuel cells/ separate hydrogen/ oxygen/ water.
Petrol will be replaced by fuel cells to separate hydrogen and oxygen in water.
4. Cars/ have sensors/ detect pedestrians/ other cars/ and/ have/ air cushions.
Cars will have sensors that detect pedestrians and other cars and will have air cushions.
5. Vehicles/ “talk”/ each other/ regulate flow/ it/ mean/ end/ traffic jams.

Vehicles can ''talk'' to each other to regulate flow, it means the end of traffic jams.(tham khảo c5)

6. Cars/ powered by fuel cells/ already developed.
Cars which are powered by fuel cells have already been developed.
7. We/ see/ this type of cars/ the roads/ twenty years.
We will see this type of cars on the roads in twenty years.
8. Environmental and safety improvements/ popular soon.
Environmental and safety improvements will be popular soon.