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22 tháng 2 2020

\(A=\frac{5}{13}+\frac{-5}{7}+\frac{-20}{41}+\frac{8}{13}+\frac{-21}{41}\)

\(\Leftrightarrow A=\left(\frac{5}{13}+\frac{8}{13}\right)+\left(\frac{-20}{41}+\frac{-21}{41}\right)+\frac{-5}{7}\)

\(\Leftrightarrow A=1+\left(-1\right)+\frac{-5}{7}\)

\(\Leftrightarrow A=0+\frac{-5}{7}=\frac{-5}{7}\)

Vậy A = \(\frac{-5}{7}\)

B= \(\frac{-5}{9}+\frac{8}{15}+\frac{-2}{11}+\frac{4}{-9}+\frac{7}{15}\)

\(\Leftrightarrow B=\frac{-5}{9}+\frac{8}{15}+\frac{-2}{11}+\frac{-4}{9}+\frac{7}{15}\)

\(\Leftrightarrow B=\left(\frac{-5}{9}+\frac{-4}{9}\right)+\left(\frac{8}{15}+\frac{7}{15}\right)+\frac{-2}{11}\)

\(\Leftrightarrow B=-1+1+\frac{-2}{11}\)

\(\Leftrightarrow B=0+\frac{-2}{11}\)

\(\Leftrightarrow\) \(B=\frac{-2}{11}\)

Vậy \(B=\frac{-2}{11}\)

@@ Học tốt

Chiyuki Fujito

K cần tk nhá

22 tháng 2 2020

Thanks bn nha

21 tháng 6 2015

a,\(=\frac{-5}{9}+\frac{8}{15}+\frac{-2}{11}+\frac{-4}{9}+\frac{7}{15}\)

\(\left(\frac{-5}{9}+\frac{-4}{9}\right)+\left(\frac{8}{15}+\frac{7}{15}\right)+\frac{-2}{11}\)

=-1+1+-2/11

=0+-2/11

=-2/11

b,\(=\left(\frac{5}{13}+\frac{8}{13}\right)+\left(\frac{-20}{41}+\frac{-21}{40}\right)+\frac{-5}{17}\)

=1+-1+-5/17

=0+-5/17

=-5/17

c,\(=\left(\frac{1}{5}+\frac{4}{5}\right)+\left(\frac{-2}{9}+-\frac{7}{9}\right)+\frac{16}{17}\)

=1+-1+16/17

=0+16/17

=16/17

d,\(=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{99}-\frac{1}{101}\)

\(=\frac{1}{3}-\frac{1}{101}=\frac{98}{303}\)

 

a.\(\frac{-5}{9}\)+\(\frac{8}{15}\)+\(\frac{-2}{11}\)+\(\frac{4}{-9}\)+\(\frac{7}{15}\)

=\(\frac{-5}{9}\)+\(\frac{4}{-9}\)+\(\frac{8}{15}\)+\(\frac{7}{15}\)+\(\frac{-2}{11}\)

=(\(\frac{-5}{9}\)+\(\frac{-4}{9}\))+(\(\frac{8}{15}\)+\(\frac{7}{15}\))+\(\frac{-2}{11}\)

=(-1)+1+\(\frac{-2}{11}\)

=0+\(\frac{-2}{11}\)

=\(\frac{-2}{11}\).

 

26 tháng 7 2016

p) \(\frac{-5}{9}+\frac{8}{15}+\frac{-2}{11}+\frac{4}{-9}+\frac{7}{15}\)

\(=\left(\frac{-5}{9}+\frac{-4}{9}\right)+\left(\frac{8}{15}+\frac{7}{15}\right)+\frac{-2}{11}\)

\(=-1+1+\frac{-2}{11}\)

\(=-\frac{2}{11}\)

q) \(\frac{5}{13}+\frac{-5}{17}+\frac{-20}{41}+\frac{8}{13}+\frac{-21}{41}\)

\(=\left(\frac{5}{13}+\frac{8}{13}\right)+\left(\frac{-20}{41}+\frac{-21}{41}\right)+\frac{-5}{17}\)


\(=1+\left(-1\right)+\frac{-5}{17}=\frac{-5}{17}\)

r) \(\frac{1}{5}+\frac{-2}{9}+\frac{-7}{9}+\frac{4}{5}+\frac{16}{17}\)

\(=\left(\frac{1}{5}+\frac{4}{5}\right)+\left(\frac{-2}{9}+\frac{-7}{9}\right)+\frac{16}{17}\)

\(=1+\left(-1\right)+\frac{16}{17}=\frac{16}{17}\)

3 tháng 6 2016

a/ 545/273

b/ 5/11

c/ -1

7 tháng 3 2017

\(\frac{5}{13}+-\frac{5}{17}+-\frac{20}{41}+\frac{8}{13}+-\frac{21}{41}\)

\(=\left(\frac{5}{13}+\frac{8}{13}\right)+\left(-\frac{20}{41}+-\frac{21}{41}\right)+-\frac{5}{17}\)

\(=1+\left(-1\right)+-\frac{5}{17}\)

\(=0+-\frac{5}{17}\)\(=-\frac{5}{17}\)

Ủng hộ tk Đúng nhé mọi người !!! ^^ 

18 tháng 8 2017

\(A=\frac{5}{13}+\frac{-5}{7}+\frac{-20}{41}+\frac{8}{13}+\frac{-21}{41}\)

\(A=\left(\frac{5}{13}+\frac{8}{13}\right)+\left(-\frac{20}{41}+\frac{-21}{41}\right)+\left(-\frac{5}{7}\right)\)

\(A=1+\left(-1\right)-\frac{5}{7}\)

\(A=0+\left(-\frac{5}{7}\right)\)

\(A=-\frac{5}{7}\)

18 tháng 8 2017

A=5/13-5/7-20/41+8/13-21/41

A=5/13+8/13-20/41-21/41-5/7

A=13/13-41/41-5/7

A=1-1-5/7

A=0-5/7

A=-5/7

Vậy A=-5/7

tk nha bn

24 tháng 6 2017

\(a,\)\(x+\frac{4}{5.9}+\frac{4}{9.13}+\frac{4}{13.17}+...+\frac{4}{41.45}=-\frac{37}{45}\)

  \(x+\left(\frac{9-5}{5.9}+\frac{13-9}{9.13}+\frac{17-13}{13.17}+...+\frac{45-41}{41.45}\right)=-\frac{37}{45}\)

  \(x+\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+\frac{1}{13}-\frac{1}{17}+....+\frac{1}{41}-\frac{1}{45}\right)-\frac{37}{45}\)

 \(x+\left(\frac{1}{5}-\frac{1}{45}\right)=-\frac{37}{45}\)

 \(x+\frac{8}{45}=-\frac{37}{45}\)

\(x=-\frac{37}{45}-\frac{8}{45}\)

\(x=-1\)

24 tháng 6 2017

thế phần b, c đâu bạn

5 tháng 9 2019

A = 5/7.(1+9/13) − 5/7.9/13

A= 5/7.(1+9/13 - 9/13)

A = 5/7.1

A = 5/7

B = 11/24 − 5/41 + 13/24 + 0.5 − 36/41

B = (11/24 + 13/24) - (5/41 + 36/41) + 0.5

B = 1 - 1 + 0.5

B = 0.5

C = −4/13.5/17 + (−12/13).4/17 + 4/13

C = 4/13.(-5/17) + (−12/13).4/17 + 4/13

C = 4/13.(-5/17 + 1) + (−12/13).4/17

C = 4/13.(−12/17) + (−12/13).4/17

C = (4.-12)/(13.17) + (−12/13).4/17

C = 4/17.(−12/13) + (−12/13).4/17

C = 4/17.(−12/13).2

C = 96/221

D = (4/3 − 3/2)2 − 2.∣−1/9∣ + (−5/18)

D = (4/3 − 3/2)2 − 2.1/9+ (−5/18)

D = -1/62 - 2/9+ (−5/18)

D = -1/12 - ( 2/9+ (−5/18) )

D = -1/12 - ( 4/18+ (−5/18) )

D = -1/12 - (-1/18)

D = -1/12 + 1/18

D = -3/36 + 2/36

D = -1/36

E = (−3/4 + 2/3):5/11 + (−1/4 + 1/3):5/11

E = (−3/4 + 2/3 + (−1/4) + 1/3):5/11

E = ((−3/4 + (−1/4)) + (2/3 + + 1/3)):5/11

E = ( - 1 + 1):5/11

E = 0:5/11

E = 0

17 tháng 12 2019

Thực hiện phép tính ( bằng cách hợp lí nếu có thể):

a, \(5\frac{4}{13}.15\frac{3}{41}-5\frac{4}{13}.2\frac{3}{41}\)

\(=5\frac{4}{13}\left(15\frac{3}{41}-2\frac{3}{41}\right)\)

\(=15\frac{4}{13}\left(\frac{618}{41}-\frac{85}{41}\right)\)

\(=\frac{69}{13}.13\)

\(=69\)

b, \(6.\left(-\frac{1}{3}\right)^2-\left(\frac{1}{4}:2-\frac{7}{16}.\frac{-4}{21}\right)\)

\(=6.\frac{1}{9}-\left(\frac{1}{8}-\frac{-1}{12}\right)\)

\(=\frac{2}{3}-\left(\frac{3}{24}-\frac{-2}{24}\right)\)

\(=\frac{2}{3}-\frac{5}{24}\)

\(=\frac{16}{24}-\frac{5}{24}\)

\(=\frac{11}{24}\)

Chúc bạn hok tốt!!! lưu khánh huyền

17 tháng 12 2019

kcj