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25 tháng 9 2022

   \(\dfrac{3}{5}\).\(\dfrac{7}{9}\) + \(\dfrac{3}{5}\).\(\dfrac{2}{9}\) + \(\dfrac{3}{5}\)

\(\dfrac{3}{5}\).(\(\dfrac{7}{9}\)\(\dfrac{2}{9}\)+1)

\(\dfrac{3}{5}\).(1+1)

\(\dfrac{6}{5}\)

25 tháng 9 2022

\(\dfrac{3}{5}\times\dfrac{7}{9}+\dfrac{3}{5}\times\dfrac{2}{9}+\dfrac{3}{5}=\dfrac{3}{5}\left(\dfrac{7}{9}+\dfrac{2}{9}+1\right)=\dfrac{3}{5}\times\left(\dfrac{9}{9}+1\right)=\dfrac{3}{5}\times\left(1+1\right)=\dfrac{3}{5}\times2=\dfrac{6}{5}\)

Ta có: \(B=\dfrac{30\cdot4^7\cdot3^{29}-5\cdot14^5\cdot2^{12}}{54\cdot6^{14}\cdot9^7-12\cdot8^5\cdot7^5}\)

\(=\dfrac{3^{30}\cdot2^{15}\cdot5-5\cdot2^{17}\cdot7^5}{3^{31}\cdot2^{15}-2^{17}\cdot3\cdot7^5}\)

\(=\dfrac{2^{15}\cdot5\left(3^{30}-2^2\cdot7^5\right)}{3\cdot2^{15}\left(3^{30}-2^2\cdot7^5\right)}\)

\(=\dfrac{5}{3}\)

24 tháng 8 2023

\(\dfrac{5}{2}\)

bạn THAM KHẢO thôi nhé!

24 tháng 8 2023

Kq = 5/2 nha bạn câu này đã có người hỏi rồi bạn tự tham khảo nhé 

19 tháng 3 2020

\(A=\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{26}{7}-\frac{13}{11}+\frac{13}{23}}-\frac{\frac{3}{5}+\frac{3}{13}-0,9}{\frac{7}{91}+0,2-\frac{3}{10}}\)

\(A=\frac{155-5\left(\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}{403-13\left(\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}-\frac{\frac{3}{5}+\frac{3}{13}-\frac{9}{10}}{\frac{7}{91}+\frac{2}{10}-\frac{3}{10}}\)

\(A=\frac{155-5}{403-13}-\frac{3\left(\frac{1}{5}+\frac{1}{13}\right)-\frac{9}{10}}{\frac{7}{91}+\left(-\frac{1}{10}\right)}\)

\(A=\frac{5}{13}-\frac{\left(-\frac{9}{130}\right)}{\left(-\frac{3}{130}\right)}=\frac{5}{13}-\frac{\frac{9}{130}}{\frac{3}{130}}\)

\(A=\frac{5}{13}-\frac{9}{130}\cdot\frac{130}{3}\)

\(A=\frac{5}{13}-3=-\frac{34}{13}\)

\(B=\frac{30\cdot4^7\cdot3^{29}-5\cdot14^5\cdot2^{12}}{54\cdot6^{14}\cdot9^7-12\cdot8^5\cdot7^5}\)

\(B=\frac{30\cdot\left(2^2\right)^7\cdot3^{29}-5\cdot\left(2\cdot7\right)^5\cdot2^{12}}{54\cdot\left(2\cdot3\right)^{14}\cdot\left(3^2\right)^7-12\cdot\left(2^3\right)^5\cdot7^5}\)

\(B=\frac{30\cdot2^{14}\cdot3^{29}-5\cdot2^5\cdot7^5\cdot2^{12}}{54\cdot2^{14}\cdot3^{14}\cdot3^{14}-12\cdot2^{15}\cdot7^5}\)

\(B=\frac{30\cdot3^{29}-5\cdot2^{17}\cdot7^5}{54\cdot3^{28}-12\cdot2^{15}\cdot7^5}=\frac{30\cdot3-5\cdot2^2}{54-12}=\frac{5}{3}\)

1: \(A=\dfrac{5\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}{13\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}+\dfrac{3\left(\dfrac{1}{5}+\dfrac{1}{13}-\dfrac{3}{10}\right)}{\dfrac{1}{13}+\dfrac{1}{5}-\dfrac{3}{10}}\)

=5/13+3

=5/13+39/13

=44/13

2: \(B=\dfrac{2^{15}\cdot3^{30}\cdot5-5\cdot2^5\cdot7^5\cdot2^{12}}{3^3\cdot2\cdot2^{14}\cdot3^{14}\cdot3^{14}-2^2\cdot3\cdot2^{15}\cdot7^5}\)

\(=\dfrac{5\cdot2^{15}\left(3^{30}-2^2\cdot7^5\right)}{3^{31}\cdot2^{15}-2^{17}\cdot3\cdot7^5}\)

\(=\dfrac{5\cdot2^{15}\left(3^{30}-2^2\cdot7^5\right)}{3\cdot2^{15}\cdot\left(3^{30}-2^2\cdot7^5\right)}=\dfrac{5}{3}\)

a: \(A=\dfrac{5\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}{13\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}+\dfrac{3\left(\dfrac{1}{5}+\dfrac{1}{13}-\dfrac{3}{10}\right)}{\left(\dfrac{1}{5}-\dfrac{3}{10}+\dfrac{1}{13}\right)}\)

=5/13+3

=5/13+39/13

=44/13

b: \(B=\dfrac{3^{30}\cdot2^{15}\cdot5-5\cdot2^5\cdot7^5\cdot2^{12}}{2\cdot3^3\cdot2^{14}\cdot3^{14}\cdot3^{14}-3\cdot2^2\cdot2^{15}\cdot7^5}\)

\(=\dfrac{2^{15}\cdot5\left(3^{30}-7^5\cdot2^2\right)}{2^{15}\cdot3^{31}-3\cdot2^{17}\cdot7^5}\)

\(=\dfrac{2^{15}\cdot5\left(3^{30}-7^5\cdot2^2\right)}{2^{15}\cdot3\left(3^{30}-7^5\cdot2^2\right)}=\dfrac{5}{3}\)

3 tháng 8 2015

a) = \(\frac{1+2+3+..+11}{3}=\frac{\left(1+11\right)+\left(2+9\right)+..+\left(5+7\right)+6}{3}=\frac{12.5+6}{3}=\frac{66}{3}=22\)

3 tháng 8 2015

b)          A = \(9+\frac{9}{2}+\frac{9}{4}+\frac{9}{8}+...+\frac{9}{128}+\frac{9}{256}\)

2 x A = 18 + 9 + \(\frac{9}{2}+\frac{9}{4}+\frac{9}{8}+...+\frac{9}{128}\)

Lấy 2 x A - A = 18 - \(\frac{9}{256}\)

A = 4599/256

24 tháng 10 2016

đề sai

29 tháng 10 2016

Mik ko chắc lắm đâu nha(/Mik làm tắc nên mất phấn tắc ra TSNT)Đại số lớp 7