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Ta có: \(\left(x+2\right)\left(x^2+2x+2\right)-x\left(x-8\right)^2=\left(4x-3\right)\left(4x+3\right)\)
\(\Leftrightarrow x^3+2x^2+2x+2x^2+4x+4-x\left(x^2-16x+64\right)=16x^2-9\)
\(\Leftrightarrow x^3+4x^2+6x+4-x^3+16x^2-64x-16x^2+9=0\)
\(\Leftrightarrow4x^2-58x+13=0\)
\(\Leftrightarrow\left(2x\right)^2-2\cdot2x\cdot\frac{58}{4}+\frac{3364}{16}-\frac{789}{4}=0\)
\(\Leftrightarrow\left(2x-\frac{58}{4}\right)^2=\frac{789}{4}\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-\frac{58}{4}=\frac{\sqrt{789}}{2}\\2x-\frac{58}{4}=-\frac{\sqrt{789}}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\frac{\sqrt{789}}{2}+\frac{58}{4}=\frac{29+\sqrt{789}}{2}\\2x=-\frac{\sqrt{789}}{2}+\frac{58}{4}=\frac{29-\sqrt{789}}{2}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\frac{29+\sqrt{789}}{4}\\x=\frac{29-\sqrt{789}}{4}\end{matrix}\right.\)
Vậy: \(x\in\left\{\frac{29+\sqrt{789}}{4};\frac{29-\sqrt{789}}{4}\right\}\)
Chuyển đổi câu sao cho nghĩa không đổi :
1, The ice is very thick . We can walk on it .
→→The ice is thick .....enough for us to walk on it.......
2,These questions are quite difficult . i can't do all of them .
→→ These questions are too.....difficult for me to do all of them.....
3, I'm very sad that i wasn't accepted in that group.
→→I'm very sad not ......to be accepted in that group........
4, Please don't make any noise ; i'm very tired .
→→ I'd rather ..you not to make noise...
5, Having a vacation abroad is very interesting .
→→ It's .....interesting to have a vacation abroad.......
6, How much does it cost to mail a letter to the USA ?
→→ What is ..the price to mail a letter to the USA ?...
7, I like chocolate and she likes chocolate , too .
→→I like chocolate and so ...does she......
Chuyển đổi câu sao cho nghĩa không đổi :
1, The ice is very thick . We can walk on it .
→→The ice is thick enough for us to walk on
2,These questions are quite difficult . i can't do all of them .
→→ These questions are too difficult for me to do all of them .
3, I'm very sad that i wasn't accepted in that group.
→→I'm very sad not to be accept in that group.
4, Please don't make any noise ; i'm very tired .
→→ I'd rather you didn't make any noise. i'm very tired
5, Having a vacation abroad is very interesting .
→→ It's very interesting to have a vacation
6, How much does it cost to mail a letter to the USA ?
→→ What is the price of a letter mailing to the USA?
7, I like chocolate and she likes chocolate , too .
→→I like chocolate and so does she
Ex1:Put the words into the correct form
1,English is an interesting (interesting) and important subject.
2, The most popular after-school activities (act) in our country are football, badminton and basketball
3,Today we have literature, physics( physical ) education and history
Ex2:Rewrite the sentences without changing its meaning
1,We walk to school for fifteen minutes every morning
\(\rightarrow\) It takes..us fifteen minutes to walk to school every morning.
2,I have fewer books than he does
\(\rightarrow\) He has.more books than I do..
3, The film is very amusing
\(\rightarrow\) What..an amusing film !.
ex1
1.interesting
2.activities
3.phyics
ex2
1,We walk to school for fifteen minutes every morning
→
It takes us fifteen minutes to walk to school every morning
2,I have fewer books than he does
→
He has
3, The film is very amusing
→
What an amusing film !
1.This novel is more interesting than any other novel
→→This is the most interesting novel I have read
2.Have you got a cheaper book than this?
→→Is this the cheapest carpet you have got?
5.Yesterday the temperature was nine degrees.Today it's only six degrees
→→It's today's which is lower than yesterday's......................
6.Tom works harder than Peter
→→Peter works lazier than Tom.....................
12.Do you a cheaper computer than this?
→→Is this the cheapest computer do you have?
13.It isn't important for you to finish the work today
→→You don't need to finish work today.........
14.He speaks E.L well
→→He is a good speaker E.L...................
1. The movie is very interesting. ⇒⇒What............an intersting movie....................!
2.The chair is very comfortable. ⇒⇒What...........a comfortable chair......................!
3.The car is very fast .⇒⇒What..........a fast car...................!
4.That students are excellent.⇒⇒What.........excellent students..................!
1. The movie is very interesting. ⇒⇒What an.interesting movie.!
2.The chair is very comfortable. ⇒⇒What a..comfortable chair.!
3.The car is very fast .⇒⇒What.a fast car............................!
4.That students are excellent.⇒⇒What.excellent.students.are.!
ko bít câu cuoi đúng ko
VI:Rewrite the fllowing sentences
1.My sister likes badminton more than soccer
→→My sister prefers................badminton to soccer..........................
3.Children should go to bed early
→→Children ought..........to go to bed early...................................
4.My children like comics very much
→→My children are interested.................in comics very much...................
5.My friend is good singer
→→My friend...........sings well....................................................
6.This cinema often shows very good films
→→There..........are many good films in this cinema...........................................................
10.I have a plan to see a detective movie with my parents tonight
→→I am.........going to see a detective movie with my parents tonight...............................................................
14.The film was made 20 years ago.Many people have enjoyed seeing it (However)
→→.............The film was made 20 years ago; however, Many people have enjoyed seeing it....................................................................
15.This is his first role.His acting is excellent. (nevertheness)
→→.............This is his first role; nevertheless, His acting is excellent.....................................................................................
16.The film didn't receive good investment.the film was a great seccess (dispite)
→→........despite receiving bad investment, the film was a great seccess ............................................................................................
18.The ending of the film was quite sisappoiting
→→We...........were disappointed about The ending of the film ...................................................................................
19.Although she performed well,she didn't receive good comments from critics
→→Dispite her.......good performance, she didn't receive good comments from critics.........................................................................
20.This film made a strong impression on me (impressed)
→→..........i was very impressed by This film.........................................................................................
21.Horror films terrify my younger sister (terrified)
→→......my younger sister is terrified of Horror films...........................................................................................
22.His new film is really surprising me (surprised)
→→......................i am surprised at His new film............................................................................
23.I found the film exciting (excited)
→→..............i am excited about the film ....................................................................................
24.The film bored us,so we left halfway through it (boring)
→→.......the film was so boring that we left halfway through it ..................................
Complete the sentences by using tootoo and eithereither
1 Everything is not OK, and (THIS PROBLEM)
→→Everything is not OK, and THIS PROBLEM is, either
Everything is not OK, and neither is THIS PROBLEM
2 Everyone knows him, and (I)
→→Everyone knows him, and I do, too
Everyone knows him, and so do I
3 Nobody knew why he was absent,and (I)
→→.Nobody knew why he was absent,and I didn't, either
.Nobody knew why he was absent,and neither did I
4 The workers must be working very hard, and (YOU)
→→The workers must be working very hard, and you must, too
The workers must be working very hard, and so must you
5 You'd have come, and (I)
→→You'd have come, and i would have too
You'd have come, and so would have i
Rewrite the following sentences:
1. Don't forget to lock the front door before you leave
⇒⇒ Be sure......to lock the front door before you leave...........
2. Going swimming in the summer is very interesting
⇒⇒ It's ...very interesting to go swimming in the summer............
3. I'm very glad to see you again
⇒⇒ It's..........very nice to see you again ..............
4. Nam will be eighteen next month
⇒⇒ It wll be.........my eighteenth birthday next month ........
5. Hoa is better at playing tennis than me
⇒⇒ Hoa plays.........tennis better than I do..................
I don't ...........play tennis as well as Hoa does..................
6. I don't make friends easily
⇒⇒ I have a lot ......of difficulty in making friends...........
7.He is able to draw much more beautifully than his friend
⇒⇒ His friend can't .........draw as beautifully as he can..................
8. My sister couldn't swim last year
⇒⇒ My sister wasn't ..........able to swim last year................
9. The dictionary is 5 inches thick
⇒⇒ The dictionary............thicks 5 inches................
1. Be sure to lock the front door before you leave.
2. It's interesting to go swimming in the summer.
3. It's such a pleasure to see you all again.
4. It will be my eighteenth birthday next month.
5.
Hoa plays tennis better than me.
I don’t play tennis better than Hoa.
6. I have a lot difficult to making friends.
7. His friend can't draw as beautifully as he can.
8. My sister wasn't able to swim last year.
9. The dictionary thicks 5 inches.
Is very important to having a balanced diet.