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5 tháng 10 2022
Câu 1:
\(=\dfrac{15}{34}+\dfrac{19}{34}-1-\dfrac{15}{17}+\dfrac{1}{3}+\dfrac{3}{5}\)
\(=-\dfrac{15}{17}+\dfrac{14}{15}=\dfrac{13}{255}\)
Câu 2:
\(=\dfrac{5^4\cdot5^4\cdot2^8}{4^4\cdot6^4\cdot3^2\cdot5}=\dfrac{5^7}{6^4\cdot3^2}\)
M
23 tháng 9 2018
a, \(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-\dfrac{20}{15}+\dfrac{3}{7}\)
= \(\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\left(\dfrac{7}{21}+\dfrac{3}{7}\right)-\dfrac{20}{15}\)
= 1 + \(\dfrac{16}{21}-\dfrac{20}{15}\)
= \(\dfrac{3}{7}\)
b, \(\dfrac{27}{25}+\dfrac{4}{21}-\dfrac{2}{25}+\dfrac{17}{21}-\dfrac{1}{2}\)
= \(\left[\dfrac{27}{25}+\left(-\dfrac{2}{25}\right)\right]+\left(\dfrac{4}{21}-\dfrac{7}{21}\right)-\dfrac{1}{2}\)
= 1 + \(\left(\dfrac{-1}{7}\right)-\dfrac{1}{2}\) = \(\dfrac{5}{14}\)
TA
2
15 tháng 10 2017
\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-\dfrac{3}{1}+\dfrac{7}{21}+2\)
\(=\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\left(\dfrac{7}{21}+\dfrac{7}{21}\right)-\left(3-2\right)\)
\(=1-1+\dfrac{14}{21}\)
\(=\dfrac{14}{21}\)
15 tháng 10 2017
\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-3+\dfrac{7}{21}+2\)
= \(\dfrac{15}{34}+\dfrac{19}{34}+\dfrac{7}{21}+\dfrac{7}{21}-3+2\)
= \(\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\left(\dfrac{7}{21}+\dfrac{7}{21}\right)-\left(3-2\right)\)
= \(1+\dfrac{2}{3}-1\)
= \(1-1+\dfrac{2}{3}\)
= \(\dfrac{2}{3}\)
GOOD LUCK!
29 tháng 11 2022
=(15/34+9/34-15/17)+(1/3+2/3)
=(24/34-15/17)+1
=-3/17+1
=14/17
LH
1
T
22 tháng 10 2023
\(\dfrac{15}{34}-\dfrac{7}{21}+\dfrac{19}{34}-\dfrac{15}{17}-\dfrac{2}{3}\)
\(=\left(\dfrac{15}{34}+\dfrac{19}{34}\right)-\left(\dfrac{7}{21}+\dfrac{2}{3}\right)-\dfrac{15}{17}\)
\(=1-\left(\dfrac{7}{21}+\dfrac{14}{21}\right)-\dfrac{15}{17}\)
\(=1-1-\dfrac{15}{17}\)
\(=-\dfrac{15}{17}\)
DX
26 tháng 7 2021
\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-\dfrac{32}{17}+\dfrac{2}{3}\)
\(=\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\dfrac{7}{21}+\dfrac{-32}{17}+\dfrac{2}{3}\)
\(=1+\dfrac{1}{3}+\dfrac{-32}{17}+\dfrac{2}{3}\)
\(=1+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\dfrac{-32}{17}\)
\(=1+1+\dfrac{-32}{17}\)
\(2+\dfrac{-32}{17}=\dfrac{2}{17}\)
23 tháng 12 2017
\(A=\dfrac{15}{34}+\dfrac{1}{3}+\dfrac{9}{34}-\dfrac{32}{17}+\dfrac{2}{3}\)
\(A=\dfrac{15}{34}+\dfrac{1}{3}+\dfrac{9}{34}-\dfrac{64}{34}+\dfrac{2}{3}\)
\(A=\left(\dfrac{15}{34}+\dfrac{9}{34}-\dfrac{64}{34}\right)+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)\)
\(A=\dfrac{40}{34}+1=2\dfrac{6}{34}\)
23 tháng 12 2017
\(A=\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{9}{34}-1\dfrac{15}{17}+\dfrac{2}{3}\)
\(=\dfrac{15}{34}+\dfrac{1}{3}+\dfrac{9}{34}-1\dfrac{15}{17}+\dfrac{2}{3}\)
\(=\left(\dfrac{15}{34}+\dfrac{9}{34}\right)+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)-1\dfrac{15}{17}\)
\(=1+1-1\dfrac{15}{17}\)
\(=2-1\dfrac{15}{17}\)
\(=\dfrac{2}{17}\)
25 tháng 10 2018
Thực hiện phép tính bằng cách tính hợp lí
a)\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-1\dfrac{15}{17}+\dfrac{2}{3}=\)
=\(\dfrac{15}{34}+\dfrac{1}{3}+\dfrac{19}{34}-1\dfrac{15}{17}+\dfrac{2}{3}\)
=\(\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)-1\dfrac{15}{17}\)
=\(1+1-\dfrac{32}{17}\)
=\(\dfrac{34}{17}-\dfrac{32}{17}\)
=\(\dfrac{2}{17}\)
b)\(\left(-2\right)^3\cdot\left(\dfrac{3}{4}-0,25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
=\(-8\cdot\left(\dfrac{3}{4}-\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
=\(-8\cdot\dfrac{1}{2}:\left(\dfrac{54}{24}-\dfrac{28}{24}\right)\)
=\(-4:\dfrac{13}{12}\)
=\(-4\cdot\dfrac{12}{13}\)
=\(-\dfrac{48}{13}\)
\(\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-1\dfrac{15}{17}+\dfrac{2}{3}\)
= \(\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\left(\dfrac{7}{21}+\dfrac{2}{3}\right)-1\dfrac{15}{17}\)
= \(1+\left(\dfrac{7}{21}+\dfrac{14}{21}\right)-1\dfrac{15}{17}\)
= \(1+1-1\dfrac{15}{17}\)
= \(2-1\dfrac{15}{17}\)
= \(\dfrac{2}{17}\)