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29 tháng 8 2021

a, \(\left(y-2\right)\left(y+2\right)\left(y^2+4\right)-\left(y+3\right)\left(y-3\right)\left(y^2+9\right)\)

\(=\left(y^2-4\right)\left(y^2+4\right)-\left(y^2-9\right)\left(y^2+9\right)\)

\(=y^4-16-y^4+81=65\)

b, \(2\left(x^2-xy+y^2\right)\left(x-y\right)\left(x^2+xy+y^2\right)\left(x+y\right)-2\left(x^6-y^6\right)\)

\(=2\left(x^3-y^3\right)\left(x^3+y^3\right)-2\left(x^6-y^6\right)\)

\(=2\left(x^6-y^6\right)-2\left(x^6-y^6\right)=0\)

22 tháng 3 2020

B. a<0,b<0.

28 tháng 8 2021

HOC dot

28 tháng 8 2021

\(\left(a+b+c\right)^2=a^2+b^2+c^2+2ab+2bc+2ac\)

\(\left(a+b-c\right)^2=a^2+b^2+c^2+2ab-2bc-2ac\) 

\(\left(a-b-c\right)^2=a^2+b^2+c^2-2ab+2bc-2ac\)

\(\left(x-2y+1\right)^2=x^2+4y^2+1-4xy-4y+2x\)

\(\left(3x+y-2\right)^2=9x^2+y^2+4+6xy-12x-4y\)

1.Mai and Lan don't play soccer in the afternoon.

Do Mai and Lan play soccer in the afternoon?

2.Her teacher doesn't listen to music every day.

Does her teacher listen to music every day?

k cho mình nhé

18 tháng 6 2021

III. Hãy chuyn nhng câu sau sang câu ph định và nghi vn

1.Mai and Lan play soccer in the afternoon.

…Mai and Lan don't play soccer in the afternoon……………………………………………………

Do Mai and Lan play soccer in the afternoon…?………………………………………………………

2. Her teacher listens to music every day.

Her teacher doesn't listen to music every day……………………………………………

Does her teacher listen to music every day ?…………………………………………………………………………

10 tháng 11 2021

D

IV. Đọc đoạn văn sau và trả lời câu hỏiNam is a student. He’s in grade six. Every morning, he gets up at half past five. He brushes his teeth at five forty-five, washes his face and gets dressed, and then he has his big breakfast at six o’clock. He goes to school at six thirty. Nam’s school is small. It has two floors and Nam’s classroom is on the second floor.1. What does Nam do?………………………………………………………………………………2....
Đọc tiếp

IV. Đọđon văn sau và tr li câu hi

Nam is a student. He’s in grade six. Every morning, he gets up at half past five. He brushes his teeth at five forty-five, washes his face and gets dressed, and then he has his big breakfast at six o’clock. He goes to school at six thirty. Nam’s school is small. It has two floors and Nam’s classroom is on the second floor.

1. What does Nam do?

………………………………………………………………………………

2. Which grade is he in?

……………………………………………………………………………

3. What time does Nam brush his teeth?

……………………………………………………………………………

4. Is Nam’s school big?

…………………………………………………………………………

5. Does Nam go to school at six thirty?

……………………………………………………………………………

6. How many floors does his school have?

…………………………………………………………………

3

1.Nam is a student.

2.He's in grade six.

3.He brushes his teeth at five forty-five.

4.No,it isn't.

5.Yes,he does.

6.His school has two floors.

nếu đúng thì cho 1 k nhé

18 tháng 6 2021

Trả lời :

1 , Nam is a student .

2 , He's grade in six .

3 , He brushes his teeth at five forty - five .

4 , No, he isn't

5 , Yes , he does

6 , His school has two floors

câu hỏi

Cái gì cao lớn lênh khênh  Đứng mà không tựa ngã kềnh ra ngay

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kềnh , lênh khênh 

8 tháng 1 2022

D

HQ
Hà Quang Minh
Giáo viên
19 tháng 7 2023

a) Điểm M sẽ thuộc góc phần tư thứ I 

b) Điểm M sẽ thuộc góc phần tư thứ IV

c) Điểm M sẽ thuộc góc phần tư thứ II

d) Điểm M sẽ thuộc góc phần tư thứ III