Trả lời:

\(2xy.3x^2y^3=6x^3y^4\)

Hok tốt

:V mk dốt toán :V

\(2xy.3x^2y^3\)

\(=\left(2.3\right)\left(xy.x^2y^3\right)\)

\(=6x^3y^4\)

loại mất dạy nha không tự làm mà đi hỏi bài của bạn

Chửi hắn làm chi mồ 

S=-a+b+c-c+b-a-a-b

S=(-a+a)+(-b+b)+(-c+c)+(b-a)

S=b-a

Vì a > b nên b-a <0 do đó |S|=|b-a|=-(b-a) hay |S|=a-b

    NHỚ K MÌNH NHA ! CHÚC BẠN HỌC TỐT !

câu 1 ,2 ,3 mk làm đc r nha

4. achievements

5. competitive

6. climbing

7. player

8. famous

9. information

10. professional

11. competition

12. Congratulation

13. footballer

14. useful

15. loudly

4. achievements

5. competitive

6. climbing

7. player

8. famous

9. information

10. professional

11. competition

12. Congratulation

13. footballer

14. useful

15. loudly

Câu đầu:

A=1.1.2.2.3.3.4.4/1.2.2.3.3.4.4.5

A=(1.2.3.4).(1.2.3.4)/(1.2.3.4).(2.3.4.5)

A=1.1/1.5

A=1/5

Câu sau:

B=2.2.3.3.4.4.5.5/1.3.2.4.3.5.4.6

B=(2.3.4.5).(2.3.4.5)/(1.2.3.4).(3.4.5.6)

B=5.1/1.3

B=5/3

LƯU Ý: nếu không làm như mình thì bạn có thể làm giống hướng dẫn trong sách trừ khi cô của bạn bắt bạn cắt đáp án đi hay đại loại vậy

lp mấy mới được chứ

LỚP SÁU NHÉ CÁC BN!

52,8:4=13,2

5,28:4=1,32

9,52:6,8=1,4

95,2:681,4

755,2:3,2=236

75,52:3,2=23,6

75,52:3,3=3776/165

1/13,2

2/1,32

3/1,4

4/1,4

5/23.6

6/23.6

7/22.88.....

a)13,2; b)1,32; c)1,4 d)1.4; e) 23,6; g)23;6; h)22,884co du

Bài 2:

n) Ta có: \(N=\dfrac{4}{2\cdot4}+\dfrac{4}{4\cdot6}+\dfrac{4}{6\cdot8}+...+\dfrac{4}{2014\cdot2016}\)

\(=2\left(\dfrac{2}{2\cdot4}+\dfrac{2}{4\cdot6}+\dfrac{2}{6\cdot8}+...+\dfrac{2}{2014\cdot2016}\right)\)

\(=2\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+...+\dfrac{1}{2014}-\dfrac{1}{2016}\right)\)

\(=2\cdot\left(\dfrac{1}{2}-\dfrac{1}{2016}\right)\)

\(=2\cdot\dfrac{1007}{2016}=\dfrac{1007}{1008}\)

o) Ta có: \(\dfrac{1}{18}+\dfrac{1}{54}+\dfrac{1}{108}+...+\dfrac{1}{990}\)

\(=\dfrac{1}{3\cdot6}+\dfrac{1}{6\cdot9}+\dfrac{1}{9\cdot12}+...+\dfrac{1}{30\cdot33}\)

\(=\dfrac{1}{3}\left(\dfrac{3}{3\cdot6}+\dfrac{3}{6\cdot9}+\dfrac{3}{9\cdot12}+...+\dfrac{3}{30\cdot33}\right)\)

\(=\dfrac{1}{3}\left(\dfrac{1}{3}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{12}+...+\dfrac{1}{30}-\dfrac{1}{33}\right)\)

\(=\dfrac{1}{3}\left(\dfrac{1}{3}-\dfrac{1}{33}\right)\)

\(=\dfrac{1}{3}\cdot\dfrac{10}{33}=\dfrac{10}{99}\)

a) Ta có: \(\left(6\dfrac{4}{9}+3\dfrac{7}{11}\right)-4\dfrac{4}{9}\)

\(=\dfrac{58}{9}+\dfrac{40}{11}-\dfrac{40}{9}\)

\(=2+\dfrac{40}{11}=\dfrac{62}{11}\)

Bài 2:

b) Ta có: \(10\dfrac{1}{5}-5\dfrac{1}{2}\cdot\dfrac{60}{11}+3:15\%\)

\(=\dfrac{51}{5}-\dfrac{11}{2}\cdot\dfrac{60}{11}+3:\dfrac{3}{20}\)

\(=\dfrac{51}{5}-30+20\)

\(=\dfrac{51}{5}-10=\dfrac{1}{5}\)

c) Ta có: \(\dfrac{2}{3\cdot5}+\dfrac{2}{5\cdot7}+\dfrac{2}{7\cdot9}+...+\dfrac{2}{97\cdot99}\)

\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+...+\dfrac{1}{97}-\dfrac{1}{99}\)

\(=\dfrac{1}{3}-\dfrac{1}{99}\)

\(=\dfrac{32}{99}\)

Bài 2: 

d) Ta có: \(\dfrac{5}{7}\cdot\dfrac{5}{11}+\dfrac{5}{7}\cdot\dfrac{2}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}\)

\(=\dfrac{5}{7}\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)\)

\(=\dfrac{5}{7}\cdot\dfrac{-7}{11}\)

\(=-\dfrac{5}{11}\)

e) Ta có: \(\dfrac{-5}{7}\cdot\dfrac{2}{11}+\dfrac{-5}{7}\cdot\dfrac{9}{11}+1\dfrac{5}{7}\)

\(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{12}{7}\)

\(=\dfrac{12}{7}-\dfrac{5}{7}=1\)

a) Ta có: \(19\dfrac{5}{8}:\dfrac{7}{12}+\left(-15\dfrac{1}{4}\right):\dfrac{7}{12}\)

\(=\dfrac{157}{8}\cdot\dfrac{12}{7}-\dfrac{61}{4}\cdot\dfrac{12}{7}\)

\(=\dfrac{12}{7}\left(\dfrac{157}{8}-\dfrac{61}{4}\right)\)

\(=\dfrac{12}{7}\cdot\dfrac{35}{8}=5\cdot\dfrac{3}{2}=\dfrac{15}{2}\)

                                         Sau khi giặt , mỗi 1m vải theo chiều dài sẽ còn lại :

                                                   15/16.17/18.8/10=17/24 (m²) vải

                           => Phải mua 24m để sau khi giặt có 17m² vải

câu tra loi cua Quy Nha Thiên giong trong sach giai, ma sach giai chi ghi co nhieu do thoi.                                                                        vay ban tim o dau ma co dc 15/16, 17/18 va 8/10 dzi. van de chinh la phai tim dc nhg phan so do bang cach nao da. lop mk cung dg dau voi bai nay ne.