\(\dfrac{5^4.20^4}{25^5.4^5}=\dfrac{5^4.5^44^4}{5^4.5.5^4.5.4^4.4}=\dfrac{5^8.4^4}{5^4.5^4.5.5.4^4.4.4.}=\dfrac{5^8.4^4}{5^8.5^2.4^4.4}\)\(=\dfrac{1}{5^2.4}=\dfrac{1}{100}=0,01\)
c)
\(\dfrac{5^4.20^4}{25^5.4^5}\)
\(=\dfrac{5^4.\left(5.4\right)^4}{\left(5^2\right)^5.\left(2^2\right)^5}\)
\(=\dfrac{5^4.5^4.4^4}{5^{10}.2^{10}}\)
\(=\dfrac{5^8.\left(2^2\right)^4}{5^{10}.2^{10}}\)
\(=\dfrac{5^8.2^8}{5^{10}.2^{10}}\)
\(=\dfrac{1}{5^2.2^2}\)
\(=\dfrac{1}{25.4}\)
\(=\dfrac{1}{100}\)
\(a,\left(\dfrac{3}{7}+\dfrac{1}{2}\right)^2=\left(\dfrac{6}{14}+\dfrac{7}{14}\right)^2=\left(\dfrac{13}{14}\right)^2=\dfrac{169}{196}\)
\(b,\left(\dfrac{3}{4}-\dfrac{4}{5}\right)^2=\left(\dfrac{15}{20}-\dfrac{16}{20}\right)^2=\left(\dfrac{-1}{20}\right)^2=\dfrac{1}{400}\)
\(c,\dfrac{5^4\cdot20^4}{25^5\cdot4^5}=\dfrac{\left(5\cdot20\right)^4}{\left(25\cdot4\right)^5}=\dfrac{\left(100\right)^4}{\left(100\right)^5}=\dfrac{100000000}{10000000000}=\dfrac{1}{100}\)
\(d,\dfrac{\left(\dfrac{2}{3}\right)^3\cdot\left(\dfrac{-3}{4}\right)^2\cdot\left(-1\right)^{2003}}{\left(\dfrac{2}{5}\right)^2\cdot\left(-\dfrac{5}{12}\right)^3}=\dfrac{\dfrac{8}{27}\cdot\dfrac{9}{16}\cdot\left(-1\right)}{\dfrac{4}{25}\cdot\left(-\dfrac{125}{1728}\right)}\)
\(=\dfrac{\dfrac{72}{432}\cdot\left(-1\right)}{\left(-\dfrac{500}{43200}\right)}=\dfrac{\dfrac{1}{6}\cdot\left(-1\right)}{\left(-\dfrac{5}{432}\right)}=\dfrac{-\dfrac{1}{6}}{-\dfrac{5}{432}}=\dfrac{72}{5}\)