\(x^2=x\)

\(=>\left[{}\begin{matrix}x=1\\x=0\end{matrix}\right.\)

Gọi các phân số bé hơn \(\dfrac{6}{7}\) và lớn hơn \(\dfrac{6}{8}\) là \(x\)

Ta có: \(\dfrac{6}{8}< x< \dfrac{6}{7}\)

\(=>\dfrac{42}{56}< x< \dfrac{42}{49}\)

Vậy 5 phân số đó là: \(\dfrac{42}{55};\dfrac{42}{54};\dfrac{42}{53};\dfrac{42}{52};\dfrac{42}{51}\)

Để \(x\) là số nguyên thì \(2⋮2a+1\)

\(=>2a+1\inƯ\left(2\right)=\left\{-2;-1;1;2\right\}\)

\(->2a\in\left\{-3;-2;0;1\right\}\)

\(=>a\in\left\{\dfrac{-3}{2};-1;0;\dfrac{1}{2}\right\}\)

\(\)Vì \(a\) là số nguyên \(=>a\in\left\{-1;0\right\}\)

III

1. My brother's school is smaller than mine

\(\widehat{xOy}+\widehat{x'Oy=180^0}\)  (Vì \(\widehat{xOy}\) và \(\widehat{x'Oy}\) là hai góc kề bù)

\(\widehat{xOy}-\widehat{x'Oy}=40^0\)

a.\(\widehat{xOy}=\left(180^0+40^0\right):2=110^0\)

\(\widehat{x'Oy'}=\widehat{xOy}=110^0\) ( 2 góc đối đỉnh)

b. \(\widehat{x'Oy}=180^0-\widehat{xOy}=180^0-110^0=70^0\) (2 góc kề bù)

\(\widehat{xOy'}=\widehat{x'Oy}=70^0\) ( 2 góc đối đỉnh)

I. Tense of verbs

1. School (finishes)  at 4.30 p.m. every day.

 -> finishes

2. Do you often (eat)  lunch in the school canteen?

-> eat

3He(watch) TV in the afternoon?

-> Does he watch

4. It's warm today. I (do not want)to   (stay)  at home now. What about (go)  swimming in the river?

-> don't want/ stay/ going

5. Listen!  they (sing)  in the classroom?

-> are singing

6. My family likes (spend)  our summer holidays at the seaside.

-> spending

7. We should( get) up early.

-> get

8 She wants(to buy) some books and some pens.

-> to buy

9.Nam(study) E every day.

-> studies

10. My mother ( have) rice every day.

-> has

II. Sound

1.A.eating               B.reading               C.teacher      D.breakfast

2.A.Thursday          B.thanks                 C.these         D.birthday

3.A.open                 B.doing                  C.going        D.cold

4. Advice                B.price                   C.nice          D.police

5.A.city                   B.cathedral             C.central      D.cinema

6A.treat                   B.clean                   C.great         D.beach

7. plays                   makes                     tents   D. phones

III. Writing
1. My school is bigger than my brother's school.

Your school (? làm gì có your school)

-> My brother's school is smaller than my 

2 Life in the city is more expensive than life in the countryside.

Life in the countryside is cheaper than life in the city

3. Peter's lessons   are shorter than Nick's lessons

Nick's lessons are longer than Peter's lessons

1. Uniform is worn at school by student

2. Ao dai is worn by Vietnamese  on special day women

\(95-\left(3x-27\right).39=4212\)

\(95-\left(3x-27\right)=108\)

\(3x-27=-13\)

\(3x=14\)

\(x=\dfrac{14}{3}\)

\(B=8x^3+12x^2+6x+1\)

\(=8\left(\dfrac{1}{2}\right)^3+12\left(\dfrac{1}{2}\right)^2+6.\dfrac{1}{2}+1\)

\(=8.\dfrac{1}{8}+12.\dfrac{1}{4}+3+1\)

\(=1+3+4\)

\(=8\)

um xong để đấy à? nói vậy ai chả nói được? quan trọng phải biết thay đổi chứ