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a) \(\left(3^5\times3^7\right):3^{10}+5\times2^4-7^3:7=3^{12}:3^{10}+5\times2^4-7^2\)
\(=3^2-5\times16-7^2=9-80-49=-120\)
b) \(15:\left(3^5:3^4\right)-2^9:2^7=15:3-2^2=5-4=1\)
c)\(5\times3^5:\left(3^8:3^5\right)-2^3\times5=5\times3^5:3^3-2^3\times5\)
\(=5\times3^2-2^3\times5=5\times9-8\times5=45-40=5\)
Bài 2:
a: =>3/4x=-3/5-1/2=-11/10
\(\Leftrightarrow x=\dfrac{-11}{10}:\dfrac{3}{4}=\dfrac{-11}{10}\cdot\dfrac{4}{3}=-\dfrac{44}{30}=-\dfrac{22}{15}\)
b: \(\Leftrightarrow x+\dfrac{3}{4}x=\dfrac{1}{3}+\dfrac{5}{4}=\dfrac{19}{12}\)
=>7/4x=19/12
=>x=19/21
c: \(\Leftrightarrow-\dfrac{2}{3}x+\dfrac{1}{6}=\dfrac{2}{3}x-\dfrac{1}{3}\)
=>-4/3x=-1/3-1/6=-1/2
=>x=1/2:4/3=1/2x3/4=3/8
Bài 1
\(\dfrac{1}{7}:\dfrac{5}{17}-\dfrac{3}{2}.\left(\dfrac{1}{6}-\dfrac{7}{12}\right)\)
\(\dfrac{1}{7}.\dfrac{17}{5}-\dfrac{3}{2}.\left(-\dfrac{5}{12}\right)\)
\(\dfrac{17}{35}-\left(-\dfrac{5}{8}\right)\)
\(\dfrac{17}{35}+\dfrac{5}{8}\)
\(\dfrac{311}{280}\)
a: \(\dfrac{3}{5}-\dfrac{7}{4}=\dfrac{12}{20}-\dfrac{35}{20}=\dfrac{-23}{20}\)
b: \(\dfrac{4}{5}:\dfrac{-8}{15}=\dfrac{-4}{5}\cdot\dfrac{15}{8}=\dfrac{-60}{40}=\dfrac{-3}{2}\)
c: \(=7+\dfrac{5}{9}-2-\dfrac{3}{4}-3-\dfrac{5}{9}=2-\dfrac{3}{4}=\dfrac{5}{4}\)
d: \(=\dfrac{-3}{7}\left(\dfrac{4}{19}+\dfrac{15}{19}\right)+\dfrac{5}{7}=\dfrac{2}{7}\)
à