a) 1,2-(x-0,8)= -2(0,9+x)

VT=-(x-2)

VP=\(-\frac{10x+9}{5}\)

pt trở thành:-(x-2)=\(-\frac{10x+9}{5}\)

<=>2-x=-2x-1,8

<=>5x=-19

<=>x=-3,8

ta gọi chiều rộng là b
chiều dài là a
ta có :
a x b=S
(b+b) xb = S
(b x b) +(b x b) = S
 (b x b) +(b xb) = 32km2
( bx b) X 2 = 32km2
( bx b) = 32 :2 
( bx b) = 16
 16 là tích của 2 thừa số giống nhau ( 4x 4 )
vậy chiều rộng = 4 km
chiều dài là : 4 x 2= 8 km
chu vi khu rừng : ( 8+4) x2 = 24 (km )

Đúng lúc sắp thí, thanks chị nhiều nhá !!

a)(x-1)(x²+5x-2)-(x³-1)=0    

<=>4x²-7x+3

<=>(x-1)(4x-3)=0

<=>x-1=0 hoặc 4x-3=0

<=>x=1 hoặc x=\(\frac{3}{4}\)

b) x²+(x+2)(11x-7)=4

<=>12x²+15x-14=4

<=>12x²+14x-18=0

<=>3(4x²+5x-6)=0

<=>4x²+5x-6=0

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

<=>x+2=0 hoặc 4x-3=0

<=>x=-2 hoặc x=\(\frac{3}{4}\)

c)x³+1=x(x+1)   

<=>x³+1-x(x+1)=0

<=>(x-1)²(x+1)=0

<=>(x-1)²=0 hoặc x+1=0

<=>x=1 hoặc -1 

d) x³+x²+x+1=0

mk gõ mỏi tay rùi bạn tự làm nốt nhé

x=-1

WHAT ARE THE DISADVANTAGES OF USING MOBILE PHONE

Generally, the mobile phone will certainly bring 'bout lots of advantages that noone can deny. On the other hand, it also offers many disadvantages.

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In brief, mobile phones are neccesary for our modern lives today. However, it is helpful or not, that depends on the ways we use them. It will be better if we use them with true purpose sand in an appropriate time.

WHAT ARE THE ADVANTAGES OF USING MOBLIE PHONE

Nowadays, mobile phone play a major role in our lives, which generally brings many benifits to us.

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Although she doesn't earn much money, she spends like a millionaire

-> Despite NOT EARNING MUCH MONEY, SHE SPENDS LIKE A MILLIONARE

The girl has just gone out. Do you know her?

-> Do you know the girl WHO HAS JUST GONE OUT

If we don't leave now, we will be late

-> Unless WE LEAVE NOW, WE WILL BE LATE

I. Give the correct form of the words in the brackets into the spaces of the sentences to complete it.

1. The ancient ( Egypt) worte on a plant called papyrus.

=>EGYPTIAN

2. There was a strange ( mix) in the bowl.

=>MIXTURE

3. The wood pulp is cleaned and (chemist) whiten.

=>CHEMICALLY

4. The television is one of the most important ( invent) of the 20th century.

=>INVENTIONS

5. Paper was made from wood pulp in the year 105 by a Chinese (office).

=>OFFICIAL

6. This manual isn't very (help).

=>HELPFUL

II. Change these sentences into the passive.

1. We must write to him.

=> HE MUST BE WRITTEN TO

2. They were painting the wall at that time.

=> THE WALL WERE BEING PAINTED AT THAT TIME

3.People play football all over the world.

=>FOOTBALL IS PLAYED ALL OVER THE WORLD BY PEOPLE

4.Somebody told him to wait out side.

=> HE WAS TOLD TO WAIT OUT SIDE

5. One uses milk for making butter and cheese.

=> MILK IS USED FOR MAKING BUTTER AND CHEESE

6. They didn't tell me the truth about the situation.

=> THE TRUTH ABOUT THE SITUATION WASN'T TOLD TO ME

7. Did they build the house in 1360 ?

=> WAS THE HOUSE BUILT IN 1360?
8. They broke the window.

=> THE WINDOW WAS BROKEN