1: A ball is round

2: The table has four legs

3: My dog has white fur

4: A year has twelve months

5: I celebrate my birthday every year

1 a. various

   b. different

   c. diverse

   d. similar

2 a. agriculture

   b. economy

   c. education

   d. industrial 

f(1)=1+1³+1⁵+1⁷+…+1¹⁰¹

=1+1+1+…+1 =51.1 =51

Thay x = -1 vào f(x) ta được

f(−1)=1+(−1)³+(−1)⁵+(−1)⁷+…+(−1)¹⁰¹

=1+(−1)+(−1)+…+(−1)

=1+50.(−1)=1−50=−49 

a) Tam giác DEF cân có DE= DF , DI là trung tuyến đồng thời là đường cao,

Xét Tam giác DEI và Tam giác DFI có: DE=DF, góc DEF= góc DFE( tam giác DEF cân), EI= IF

 Tam giác DEI = Tam giác DFI (cgc)

b) từ câu a ta có góc  EID= FID (góc tương ứng)

Mà  EID+ FID = 180 ---->   EID= FID =900

DI vuông góc EF. 
                  Học tốt nha!

a,f(x)+g(x)= (x2 + 3x - 5 ) +(x2 + 2x + 3)

                = x2 +3x-5 +x2 +2x+3

                = (x2+x2) +(3x+2x) +(-5+3)

                = 2x2 +5x -2

b, f(x)-g(x)=(x2 + 3x - 5 ) -(x2 + 2x + 3)

                 = x2 + 3x - 5  -x2 - 2x - 3

                 = (x2-x2) + (3x-2x) +(-5-3)

                  = X-8
Học tốt nha!

It's very necessary to study English.

À, mình vừa nghĩ ra câu 7. Nếu có gì sao mong bạn thông cảm tí nha!!
7. You should eat enough fruit and vegetable. You should eat too much candies because you will be fatter.
Mình nghĩ vậy vì advice là lời khuyên nha.
 

1. There are ten dogs in the kennel.

2. My grandma is the oldest in my family.

3. Thuy is heavier than Tung.

4. I enjoy eating sandwich.

5. I can't eat the soup now because it is hot.
7.hừm.............ờ...........ờ..........( mk không biết nữa)

      Để cắt được sợi dây dài\(\dfrac{1}{2}\)m từ sợi dây dài \(\dfrac{2}{3}\)m mà không cần thước đo thì ta làm như sau:
+ Gập đôi sợi dây lại thì ta có sợi dây mói dài \(\dfrac{1}{3}\)m.
+ Lấy \(\dfrac{1}{3}\)m đó, gập đôi tiếp để có sợi dây dài \(\dfrac{1}{6}\)m.
+ Rồi ta lấy phần \(\dfrac{1}{6}\)m dây đó (cầm phần đầu sợi dây) rồi gấp dọc theo sợi dây thêm 2 lần nữa thì tổng cộng ta có được 3 lần của \(\dfrac{1}{6}\)m
=>  Ta sẽ lấy được \(\dfrac{1}{2}\)m dây từ sợi dây \(\dfrac{2}{3}\)m.
Học tốt nha!

1/ Viết lại các câu sau bằng mệnh đề điều ước
1. Unfortunately the weather is not nice.
=> I wish...the weather were nice.....
2. your cousin doesn't tell you the truth
=> I wish....your cousin told you the truth....
3. I'm sorry that you didn't study hard.
=> I wish........you had studied hard
4. I can't lend you any money
=> I wish....I could lend you some money....
5. It's a pity he didn't invite us to the party.
=> he wishes ……he had invited us to the party………………. ........
 6. I'm sorry I couldn't give an answer easily.
=> I wish.....I could give an answer easily...
7. Tom is not here now.
=> Tom wishes .......he were here now..................... ........
8. We don't buy houses.
=> we wish ……we bought houses………………. ........
2/ Viết lại các câu sau với câu điều kiện
1. today is not sunday. Students can't go swimming
=> If ……today were sunday, students could go swimming……………….
2.peter doesn't study hard, so he can't get good grades
=> If ……peter studied hard, she could get good grades……………….
3. my sister is absent from her class because she has a terrible headache
=> If ……My sister didn't have a terrible headache, she wouldn't be absent from class……………….
4. because he was lazy today, so he got a bad grade.
=> If he …hadn't been lazy today, he wouldn't have got bad grade………………….
5. If it weren't for the costs involved, I would have gotten there by air
=> unless …it were for the costs involved, I would have gotten there by air………………….
6. I don't have a car, so I don't drive to work
=> If ……I had a car, I would drive to work……………….
7. the air in this city is not fresh, so we are not healthy
=> If …the air in this city were fresh, we would be healthy…………………