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a) \(\dfrac{27^3\cdot11+9^5\cdot5}{3^9\cdot2^4}\)
\(=\dfrac{3^9\cdot11+3^{10}\cdot5}{3^9\cdot2^4}\)
\(=\dfrac{3^9\cdot\left(11+3\cdot5\right)}{3^9\cdot2^4}\)
\(=\dfrac{11+15}{16}\)
\(=\dfrac{26}{16}\)
\(=\dfrac{13}{8}\)
b) \(\dfrac{5^8+2^2\cdot25^4+2^3\cdot125^3-15^4\cdot5^4}{4^2\cdot625^2}\)
\(=\dfrac{5^8+2^2\cdot5^8+2^3\cdot5^9-3^4\cdot5^4\cdot5^4}{2^4\cdot5^8}\)
\(=\dfrac{5^8\cdot\left(1+2^2+2^3\cdot5-3^4\right)}{5^8\cdot2^4}\)
\(=\dfrac{1+4+40-81}{16}\)
\(=\dfrac{-36}{16}\)
\(=\dfrac{-9}{4}\)
c) \(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)
\(=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^8\cdot5}\)
\(=\dfrac{2^{10}\cdot3^8\cdot\left(1-3\right)}{2^{10}\cdot3^8\cdot\left(1+5\right)}\)
\(=\dfrac{-2}{6}\)
\(=-\dfrac{1}{3}\)
b) D = \(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{2015.2016}\)
= \(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{2015}-\frac{1}{2016}\)
= \(\frac{1}{2}-\frac{1}{2016}\)
Bài c mk bí quá nên ko làm đc nhưng mong bn tick 2 bài dưới cho mk với nhé
CHÚC BẠN HỌC TỐT ^_^
\(A=\dfrac{4\cdot5^{10}\cdot5^{10}}{75^{10}}=\dfrac{4\cdot5^{20}}{\left(3\cdot25\right)^{10}}=\dfrac{4\cdot5^{20}}{3^{10}\cdot25^{10}}=\dfrac{4\cdot5^{20}}{3^{10}\cdot\left(5^2\right)^{10}}=\dfrac{4\cdot5^{20}}{3^{10}\cdot5^{20}}=\dfrac{4}{3^{10}}\)
\(B=\dfrac{\left(0.8\right)^5}{\left(0.4\right)^6}=\dfrac{\left(\dfrac{4}{5}\right)^5}{\left(\dfrac{2}{5}\right)^6}=\dfrac{\left(2\cdot\dfrac{2}{5}\right)^5}{\left(\dfrac{2}{5}\right)^6}=\dfrac{2^5\cdot\left(\dfrac{2}{5}\right)^5}{\left(\dfrac{2}{5}\right)^5\cdot\dfrac{2}{5}}=\dfrac{2^5}{\dfrac{2}{5}}=2^5\cdot\dfrac{5}{2}=\dfrac{32\cdot5}{2}=80\)
\(C=\dfrac{2^{15}\cdot9^4}{6^6\cdot8^3}=\dfrac{2^{15}\cdot\left(3^2\right)^4}{\left(2\cdot3\right)^6\cdot\left(2^3\right)^3}=\dfrac{2^{15}\cdot3^8}{2^6\cdot3^6\cdot2^9}=\dfrac{2^{15}\cdot3^8}{2^6\cdot2^9}=\dfrac{2^{15}\cdot3^8}{2^{15}\cdot3^6}=\dfrac{3^8}{3^6}=3^2=9\)
\(D=\dfrac{8^{10}+4^{10}}{8^4+4^{11}}=\dfrac{\left(2^3\right)^{10}+\left(2^2\right)^{10}}{\left(2^3\right)^4+\left(2^2\right)^{11}}=\dfrac{2^{30}+2^{20}}{2^{12}+2^{22}}=\dfrac{2^{^{20}}\left(2^{10}+1\right)}{2^{12}\left(2^{10}+1\right)}=\dfrac{2^{20}}{2^{12}}=2^8=226\)
\(\frac{8^{10}+4^{10}}{8^4+4^{11}}=\frac{\left(2^3\right)^{10}+\left(2^2\right)^{10}}{\left(2^3\right)^4+\left(2^2\right)^{11}}=\frac{2^{30}+2^{20}}{2^{12}+2^{22}}=\frac{2^{20}.\left(2^{10}+1\right)}{2^{12}.\left(1+2^{10}\right)}=\frac{2^{20}}{2^{12}}=2^{20-12}=2^8\)
\(\frac{2^{15}.9^4}{6^3.8^3}=\frac{2^{15}.\left(3^2\right)^4}{2^3.3^3.\left(2^3\right)^3}=\frac{2^{15}.3^8}{2^3.3^3.2^9}=\frac{2^{15}.3^8}{2^{12}.3^3}=2^3.3^5=8.243=1944\)
Bài 1:
b) Ta có: \(D=\dfrac{-5}{10}\cdot\dfrac{-4}{10}\cdot\dfrac{-3}{10}\cdot...\cdot\dfrac{3}{10}\cdot\dfrac{4}{10}\cdot\dfrac{5}{10}\)
\(=\dfrac{-5}{10}\cdot\dfrac{-4}{10}\cdot\dfrac{-3}{10}\cdot...\cdot0\cdot...\cdot\dfrac{3}{10}\cdot\dfrac{4}{10}\cdot\dfrac{5}{10}\)
=0