Cho góc xOy khác góc bẹt , trên tia Ox lấy 2 điểm A và D trên tia Oy lấy 2 điểm C và E sao cho OD = OE và OC = OB

a, chứng minh tam giác ODC và tam giác OBE bằng nhau.

b, Gọi A là giao điểm của BE và CD . Chứng minh tam giác AOB bằng tam giác AOC .

c, Chứng minh BC vuông góc với OA.

Tìm x , biết :

1, |\(\dfrac{3}{2}\)x + \(\dfrac{1}{2}\)| = | 4x - 1 |

2, | \(\dfrac{5}{4}\)x - \(\dfrac{7}{2}\) | - | \(\dfrac{5}{8}x+\dfrac{3}{5}\) | = 0

3, | \(\dfrac{7}{5}x+\dfrac{2}{3}\) | = | \(\dfrac{4}{3}x-\dfrac{1}{4}\) |

4, | \(\dfrac{7}{8}x+\dfrac{5}{6}\) | - | \(\dfrac{1}{2}x+5\) | = 0

Rút gon :

a, A = 2x - 3,5 - | 4x + 4,8 | - 3x + 1

b, B = - | - 4 - 2,5x | + 4x - 6,2 - 5,2x

c, C = 2,2x - 6 + | 4,2 - 1,4 x | - 3x +1,2

1, Rewrite the sentence , beginning as shown :

1, I expected my friend arrived at about 4.p.m , but today it is only six degrees.

My friends..............

2, Jane cooks better than her sister.

Jane's sister...............

3, Tom is the best football player in this team.

Nobody in his team............

4, Nothing is faster than the speed of light.

The speed of light....................

5, Jack is jounger than he looks.

Jack isn't........

6, I didn't spend as much money as you do.

................

7, I have never met anyone as interesting as he is.

He is.................

Viết các câu sau theo thể bị động :

1, People invented the wheel thousands of year ago.

2, Are they building a statue of Chu Van An ?

3, Do four busy streets surround the Temple of Literature ?

4, They will not provide pencils at the test , so please bring uor own.

5, Mr . Binh hasn't taught us since the last semester.

6, A student teacher is doing that experiment.

7,Did you buy this dictionary two weeks ago ?

8, Alan's knowledge about science and technology doesn't impress me.

9, They are going to build a new school here next year.

10, I have used this computer for two years.

Đặt câu hỏi cho phần in nghiêng:

1, The farmer work very hard .

How .............

2, The summer vacation lasts for almost three months.

How long................

3, We will visit our grandmother during the vacation.

What ..........................

4, Vietnamese students work 25 hours a week .

How many......................

5, She is definitedy not lazy because she works 45 hourse a week.

Why..................

6, Hong's mother works at a supermarket.

Where.................

7, My father gets about seven public holidays every year

How many.................

8, They always go to Ha Long Bay on vacation .

How often.....................

Đặt câu cho phần in nghieng :

1, The farmer work vey hard.

How................................. ?

2, The summer vacation lasts for almost three months.

How long .......................

3, We will visit our grandmother during the vacation.

What .......................

4, Vietnamese students work 25 hours a week .

How many ............................. ?

5, She is definitely not lazy because she works 45 hours a week .

Why ............................. ?

6, Hong's mother works at a supermarket.

Where .................................

9, My father gets about seven public holidays every year.

How many ......................

10, They always go to Ha Long Bay on vacation .

How often........................

Sưu tầm các thông tin , hình ảnh về khí hậu , rừng ở Việt Nam để viết một báo cáo ngắn chứng minh rằng : Việt Nam nằm trong kiểu môi trường nhiệt đới gió mùa.

( Mình cần gấp )