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10 tháng 3

\(\dfrac{3}{5}+\dfrac{3}{20}+\dfrac{3}{44}+\dfrac{3}{77}\)

\(=\left(\dfrac{3}{5}+\dfrac{3}{20}\right)+\left(\dfrac{3}{44}+\dfrac{3}{77}\right)\)

\(=\left(\dfrac{12}{20}+\dfrac{3}{20}\right)+\left(\dfrac{21}{308}+\dfrac{12}{308}\right)\)

\(=\dfrac{15}{20}+\dfrac{33}{308}\)

\(=\dfrac{3}{4}+\dfrac{3}{28}\)

\(=\dfrac{21}{28}+\dfrac{3}{28}\)

\(=\dfrac{24}{28}\)

\(=\dfrac{6}{7}\)

Cảm ơn anh nhìu nheee🤞

24 tháng 8 2023

Sửa đề:

\(A=\dfrac{3}{5}+\dfrac{3}{20}+\dfrac{3}{44}+\dfrac{3}{77}\)

\(A=2.\left(\dfrac{3}{5}+\dfrac{3}{20}+\dfrac{3}{44}+\dfrac{3}{77}\right)\)

\(A=\dfrac{6}{10}+\dfrac{6}{40}+\dfrac{6}{88}+\dfrac{6}{154}\)

\(A=6.\left(\dfrac{1}{2.5}+\dfrac{1}{5.8}+\dfrac{1}{8.11}+\dfrac{1}{11.14}\right)\)

\(A=6.\left(\dfrac{1}{2}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{11}+\dfrac{1}{11}-\dfrac{1}{14}\right)\)

\(A=6.\left(\dfrac{1}{2}-\dfrac{1}{14}\right)\)

\(A=6.\dfrac{6}{14}\)

\(A=\dfrac{36}{14}=\dfrac{18}{7}\)

\(=\dfrac{1}{5}.3+\dfrac{1}{5}.\dfrac{3}{4}+\dfrac{1}{11}.\dfrac{3}{4}+\dfrac{1}{11}.\dfrac{3}{7}\)

\(=\dfrac{1}{5}.\left(3+\dfrac{3}{4}\right)+\dfrac{1}{11}.\left(\dfrac{3}{4}+\dfrac{3}{7}\right)\)

\(=\dfrac{1}{5}.\dfrac{15}{4}+\dfrac{1}{11}.\dfrac{33}{28}=\dfrac{3}{4}+\dfrac{3}{28}=\dfrac{6}{7}\)

AH
Akai Haruma
Giáo viên
28 tháng 2

Lời giải:

$A=(\frac{3}{5}+\frac{3}{20})+(\frac{3}{44}+\frac{3}{77})$

$=(\frac{12}{20}+\frac{3}{20})+(\frac{21}{4.11.7}+\frac{12}{4.11.7})$

$=\frac{15}{20}+\frac{33}{4.11.7}=\frac{3}{4}+\frac{3}{28}=\frac{6}{7}$

=>\(D=7\left(\dfrac{5}{42\cdot37}+\dfrac{1}{42\cdot43}+\dfrac{6}{43\cdot49}+\dfrac{10}{49\cdot59}\right)\)

\(=7\left(\dfrac{1}{37}-\dfrac{1}{42}+\dfrac{1}{42}-\dfrac{1}{43}+\dfrac{1}{43}-\dfrac{1}{49}+\dfrac{1}{49}-\dfrac{1}{59}\right)\)

=7(1/37-1/59)

=7*22/2183

\(E=5\left(\dfrac{8}{37\cdot45}+\dfrac{2}{45\cdot47}+\dfrac{3}{47\cdot50}+\dfrac{9}{50\cdot59}\right)\)

\(=5\left(\dfrac{1}{37}-\dfrac{1}{45}+\dfrac{1}{45}-\dfrac{1}{47}+...+\dfrac{1}{50}-\dfrac{1}{59}\right)\)

=5(1/37-1/59)

=>D/E=7/5

13 tháng 7 2023

ờ bn ơi

29 tháng 7 2021

\(A=9-\frac{3}{5}+\frac{2}{3}-7-\frac{7}{5}+\frac{3}{2}-3+\frac{9}{5}-\frac{5}{2}\)

\(=\left(9-7-3\right)+\left(\frac{9}{5}-\frac{7}{5}-\frac{3}{5}\right)+\left(\frac{3}{2}-\frac{5}{2}\right)\)

\(=-2-\frac{1}{5}=-\frac{11}{5}\)

1 tháng 3 2020

Bạn tham khảo thử nhé Kết quả hình ảnh cho S=5/20+5/21+5/22+5/23+....+5/49

1 tháng 3 2020

tham khảo ở đâu vậy bạn

\(\dfrac{\left[\left(\dfrac{3}{10}-\dfrac{4}{15}-\dfrac{7}{20}\right)\cdot\dfrac{5}{19}\right]}{\left[\dfrac{1}{14}+\dfrac{1}{7}-\dfrac{\left(-3\right)}{35}\right]\cdot\left(-\dfrac{4}{3}\right)}\)

\(=\dfrac{\left(\dfrac{18}{60}-\dfrac{16}{60}-\dfrac{21}{60}\right)\cdot\dfrac{5}{19}}{\left(\dfrac{5}{70}+\dfrac{10}{70}+\dfrac{6}{70}\right)\cdot\dfrac{-4}{3}}=\dfrac{\dfrac{-19}{60}\cdot\dfrac{5}{19}}{\dfrac{21}{70}\cdot\dfrac{-4}{3}}\)

\(=-\dfrac{1}{12}:\dfrac{-2}{5}=\dfrac{1}{12}\cdot\dfrac{5}{2}=\dfrac{5}{24}\)

3 tháng 7 2017

\(A=3-\frac{1}{4}+\frac{2}{3}-5-\frac{1}{3}+\frac{6}{5}-6+\frac{7}{4}-\frac{3}{2}\)
\(=3-6-5+\frac{7-1}{4}+\frac{2-1}{3}-\frac{3}{2}+\frac{6}{5}=-8+\frac{3}{2}+\frac{1}{3}-\frac{3}{2}+\frac{6}{5}=-8+\frac{1}{3}+\frac{6}{5}=-\frac{97}{15}\)

17 tháng 4 2016

\(\frac{3-\frac{1}{2}+\frac{1}{4}}{\frac{2}{3}-\frac{5}{6}-\frac{3}{4}}=\frac{\left(3-\frac{1}{2}+\frac{1}{4}\right)\left(3.4\right)}{\left(\frac{2}{3}-\frac{5}{6}-\frac{3}{4}\right)\left(3.4\right)}=\frac{36-6+3}{8-10-9}=\frac{33}{-11}=-3\)