\(1.\dfrac{27^4.4^3}{9^5.8^2}=\dfrac{3^{12}.2^6}{3^{10}.2^6}=3^2=9\)

\(2.\dfrac{8^5.3^{15}}{2^{14}.81^4}=\dfrac{2^{15}.3^{15}}{2^{14}.3^{16}}=\dfrac{2}{3}\)

Ý 1:

\(\dfrac{27^4.4^3}{9^5.8^2}=\dfrac{\left(3^3\right)^4.\left(2^2\right)^3}{\left(3^2\right)^5.\left(2^3\right)^2}=\dfrac{3^{12}.2^6}{3^{10}.2^6}=3^2=9\)

Ý 2:

\(\dfrac{8^5.3^{15}}{2^{14}.81^4}=\dfrac{\left(2^3\right)^5.3^{15}}{2^{14}.\left(3^4\right)^4}=\dfrac{2^{15}.3^{15}}{2^{14}.3^{16}}=\dfrac{2^{14}.2.3^{15}}{2^{14}.3^{15}.3}=\dfrac{2}{3}\)

a: \(=\dfrac{2^5\cdot2^{12}\cdot2^6}{2^{24}}=\dfrac{1}{2}\)

b: \(=\dfrac{12-15}{20}\cdot\left(\dfrac{10-6}{30}\right)^2\)

\(=\dfrac{-3}{20}\cdot\left(\dfrac{2}{15}\right)^2=\dfrac{-3}{20}\cdot\dfrac{4}{225}=-\dfrac{1}{375}\)

c: \(=3\cdot\dfrac{2}{5}+2:\dfrac{1}{4}=1.2+8=9.2\)

\(=\dfrac{3^8\cdot2^{10}\cdot5^6}{2^9\cdot3^6\cdot5^7}=3^2\cdot\dfrac{2}{5}=\dfrac{18}{5}\)

\(\dfrac{9^4\cdot4^5\cdot25^3}{8^3\cdot27^2\cdot5^7}\)

\(=\dfrac{\left(3^2\right)^4\cdot\left(2^2\right)^5\cdot\left(5^2\right)^3}{\left(2^3\right)^3\cdot\left(3^3\right)^2\cdot5^7}\)

\(=\dfrac{3^8\cdot2^{10}\cdot5^6}{2^9\cdot3^6\cdot5^7}\)

\(=\dfrac{3^2\cdot2\cdot1}{1\cdot1\cdot5}\)

\(=\dfrac{18}{5}\)

bài này dễ mà :

mk gõ hộ chị thôi à bạn giúp mk nha

\(\frac{27^4.4^3}{9^5.8^2}=\frac{\left(3^3\right)^4.\left(2^2\right)^3}{\left(3^2\right)^5.\left(2^3\right)^2}=\frac{3^{12}.2^6}{3^{10}.2^6}=3^2=9\)

=\(\frac{3^{12}.2^6}{3^{15}.2^6}\)

=\(\frac{3^{12}}{3^{12}.3^3}\)

=\(\frac{1}{27}\)

-2/15

-4/35

-5/3

10

-8/3

-7/2

-9

-4/3

Chúc em học giỏi

\(=\dfrac{-2}{15}\\ =\dfrac{-4}{35}\\ =-1\\ =10\\ =\dfrac{-8}{3}\\ =-7\\ =-9\\ =\dfrac{-4}{3}\)

\(\dfrac{3}{2\cdot5}+\dfrac{3}{5\cdot8}+\dfrac{3}{8\cdot11}+\dfrac{3}{11\cdot14}+\dfrac{3}{14\cdot17}\)

= \(\dfrac{1}{2}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{11}+\dfrac{1}{11}-\dfrac{1}{14}+\dfrac{1}{14}-\dfrac{1}{17}\)

\(=\dfrac{1}{2}-\dfrac{1}{17}\)

\(=\dfrac{15}{34}\)

Vì \(\dfrac{15}{34}< \dfrac{1}{2}=>\dfrac{3}{2\cdot5}+\dfrac{3}{5\cdot8}+\dfrac{3}{8\cdot11}+\dfrac{3}{11\cdot14}+\dfrac{3}{14\cdot27}< \dfrac{1}{2}\)