a, |x - 0,25 | = 1

\(\Rightarrow\left[{}\begin{matrix}x-0,25=1\\x-0,25=-1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0,25\\x=-0,75\end{matrix}\right.\)

 Vậy x ∈ {0,25 ; -0,75}

b, \(\left|x+\dfrac{1}{4}\right|-\dfrac{1}{2}=0\)

\(\Rightarrow\left|x+\dfrac{1}{4}\right|=\dfrac{1}{2}\)

\(\Rightarrow\left[{}\begin{matrix}x+\dfrac{1}{4}=\dfrac{1}{2}\\x+\dfrac{1}{4}=-\dfrac{1}{2}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{4}\\x=-\dfrac{3}{4}\end{matrix}\right.\)

Vậy \(x\in\left\{\dfrac{1}{4};-\dfrac{3}{4}\right\}\)

Do Bx // Oz => góc BOz' = góc xBO = 180^o (Do 2 góc trong cùng phía)

                   mà góc xBO = 130^o

                    => góc BOz' + 130^o = 180^o

                    => góc BOz' = 180^o - 130^o= 50^o 

Do Oz // Ny mà Oz' là tia đối của tia Oz => Oz' // Ny

=> z'ON + ONy = 180^o ( do 2 góc trong cùng phía)

mà góc ONy = 140^o

=> z'ON + 140^o = 180^o

=> z'ON             = 180^o - 140^o = 40^o

Ta thấy: góc BON = góc BOz' + z'ON = 50^o + 40^o = 90^o

 Vậy góc BON= 90^o

Hoa is skillful. She can make her own handkerchief

→ Hoa is skillful enough to make her own handkerchief

 2. Lan is intelligent. She can do the test.

→ Lan is intelligent enough to do the test 

3. The fire isn’t very hot. It won’t boil the kettle.

→ The fire isn't  hot enough to boil the kettle 

4. The ice is quite thick. The children can walk on it.

→  The ice is thick enough for the children to walk on it

5. The box is small. I can put it in my pocket.

→  The box is small enough for me to put  in my pocket

6. Mary is young. She can’t see the horror film.

→ Marry is not old enough to see horror film 

 7. His parents were poor. They couldn’t buy a new car.

→ His parents weren't rich enough to buy a new car

8. This dress is very small. She can’t wear it

→ This dress isn't big enough for her to wear 

9. He ran very quickly. He could catch the bus.

→ He ran  quickly enough to catch the bus

10. They played quite well, so they won the match.

→ They played  well enough to win the match

 II. Building sentences, using the structure with ENOUGH

1. This box/ small/ me/ put/ my pocket.

→ This box is small enough for me to put in my pocket  

2. He/ unwell/ go for a picnic/ today.

→ He isn't well enough to go for a picnic today

3. He/ strong/ carry/ the heavy suitcase.

→ He is strong enough to carry the heavy suitcase

 4. The children/ tired/ go to bed early.

→ The children are tired enough to go to bed early

5. Her son/ hungry/ eat/ three loaves of bread.

→ Her son is hungry enough to eat three loaves of bread

6. She/ sociable/ make friends easily.

→ She is sociable enough to make friends easily  

7. I / not well/ go camping today.

→ I'm not well enough to go camping today

8. The children/ tired/ go to bed early.

→ The children are tired enough to go to bed early

 9. She/ thirsty/ drink/ glass/ apple juice.

→  She is thirsty enough to drink a glass of apple juice

10. She/ not tall/ reach/ ceiling.

→ She is not tall enough to reach the celling

c, (-23,4). (- 2,5) = 58,5

d, 12,74 : (- 5,2) = -2,75

13. will come

14. are playing

15. is (your mother) doing

16. doesn't go

17. watches

18. has

1.c

2.a

3.b

4.c

5.c

6.b

7.a

8.a

9.b

10.c

11.a

12.b

she is slim and has long black hair 

1-f

2-c

3-e

4-d

5-a

6-b

từ phá hoại nha

1-b

2-d

3-e

4-a

5-c