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Bài làm :

\(\frac{4^6\times9^5+120\times6^9}{8^4\times3^{12}-6^{11}}\)

\(=\frac{\left(2^2\right)^6\times\left(3^2\right)^5+2^3\times5\times3\times\left(2\times3\right)^9}{\left(2^3\right)^4\times3^{12}-\left(2\times3\right)^{11}}\)

\(=\frac{2^{12}\times3^{10}+2^3\times5\times3\times2^9\times3^9}{2^{12}\times3^{12}-2^{11}\times3^{11}}\)

\(=\frac{2^{12}\times3^{10}\times\left(1+5\right)}{2^{11}\times3^{11}\times\left(2\times3-1\right)}\)

\(=\frac{2\times6}{3\times5}\)

\(=\frac{4}{5}\)

Học tốt nhé

\(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)

\(=\frac{\left(2^2\right)^5.\left(3^2\right)^4-2.\left(2.3\right)^9}{2^{10}.3^8+\left(2.3\right)^8.2^2.5}\)

\(=\frac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}\)

\(=\frac{2^{10}.3^8.\left(1-3\right)}{2^{10}.3^8.\left(1+5\right)}\)

\(=\frac{-1}{3}\)

28 tháng 9 2020

Ta có:

\(\frac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)

\(=\frac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^8\cdot5}\)

\(=\frac{2^{10}\cdot3^8\cdot\left(1-3\right)}{2^{10}\cdot3^8\cdot\left(1+5\right)}\)

\(=-\frac{2}{6}=-\frac{1}{3}\)

\(\frac{1}{1.2.3}+\frac{1}{2.3.4}+...+\frac{1}{8.9.10}=\frac{1}{2}.\left(\frac{1}{1.2}-\frac{1}{2.3}\right)+\frac{1}{2}.\left(\frac{1}{2.3}-\frac{1}{3.4}\right)+...+\frac{1}{2}.\left(\frac{1}{8.9}-\frac{1}{9.10}\right)\)

\(=\frac{1}{2}.\left(\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{8.9}-\frac{1}{9.10}\right)\)

\(\frac{1}{2}.\left(\frac{1}{1.2}-\frac{1}{9.10}\right)=\frac{1}{2}.\frac{22}{45}=\frac{11}{45}\)

11 tháng 12 2017

ai nhanh mik k cho

27 tháng 7 2018

\(=\frac{2^{12}\times3^{10}+2^9\times3^9\times2^3\times3\times5}{-2^{12}\times3^{12}-2^{11}\times3^{11}}\)
\(=\frac{2^{12}\times3^{10}+2^{12}\times3^{10}\times5}{-2^{11}\times3^{11}\times\left(2\times3+1\right)}\)
\(=\frac{2^{12}\times3^{10}\times\left(1+5\right)}{-2^{11}\times3^{11}\times7}\)
\(=\frac{2^{13}\times3^{11}}{-2^{11}\times3^{11}\times7}\)
\(=\frac{-4}{7}\)