\(\frac{10}{25}=\frac{10:5}{25:5}=\frac{2}{5}\)

\(\frac{5}{20}=\frac{5:5}{20:5}=\frac{1}{4}\)

\(\frac{6}{30}=\frac{6:6}{30:6}=\frac{1}{5}\)

\(\frac{60}{20}=\frac{60:20}{20:20}=3\)

\(\frac{-63}{108}\)= \(\frac{-7}{12}\)

\(\frac{-33}{-77}\)= \(\frac{3}{7}\)

\(\frac{-5}{10}\)=\(\frac{-1}{2}\)

\(\frac{14}{63}\)=\(\frac{2}{9}\)

\(\frac{-15}{25}\)=\(\frac{-3}{5}\)

\(\frac{-45}{18}\)=\(\frac{-5}{2}\)

\(\frac{12}{15}\)=\(\frac{4}{5}\)

\(\frac{20}{25}\)=\(\frac{4}{5}\)

\(\frac{31}{12}\):Là phân số tối giản

t.i.c.k nha                                           

\(A=\frac{25^{28}+25^{24}+25^{20}+...+25^4+1}{25^{30}+25^{28}+25^{26}+...+25^2+1}=25^{30}+25^{26}+25^{22}+25^{18}+25^{14}+25^{10}+25^6+25^2\)

(ĐK: \(x\ge0;x\ne25\))

\(A=\left(\frac{3\left(\sqrt{x}-5\right)+20-2\sqrt{x}}{x-25}\right).\left|x-4\right|\)

\(A=\left(\frac{\sqrt{x}+5}{x-25}\right)\left|x-4\right|=\frac{\left|x-4\right|}{\sqrt{x}-5}\)

\(\left(ĐK:x\ge0;x\ne25\right)\)

\(A=\left(\frac{3\left(\sqrt{x}-5\right)+20-2\sqrt{x}}{x-25}\right).|x-4|\)

\(A=\left(\frac{\sqrt{x}+5}{x-25}\right)|x-4|=\frac{|x-4|}{\sqrt{x}-5}\)

Chúc bạn học tốt

k nhé

\(A=\frac{4^{15}.5^{15}.3^{12}.5^{12}}{5^{28}.2^{14}.3^{14}.2^{15}}=\frac{2.2^{29}.5^{27}.3^{12}}{5.5^{27}.2^{29}.3^{12}.3^2}=\frac{2}{45}\)

\(A=\frac{20^{15}.15^{12}}{25^{14}.6^{14}.8^5}=\frac{\left(2^2.5\right)^{15}.\left(3.5\right)^{12}}{\left(5^2\right)^{14}.\left(2.3\right)^{14}.\left(2^3\right)^5}=\frac{\left(2^2\right)^{15}.5^{15}.3^{12}.5^{12}}{5^{28}.2^{14}.3^{14}.2^{15}}\)

=\(\frac{2^{30}.3^{12}.5^{15}.5^{12}}{5^{28}.3^{14}.2^{14}.2^{15}}=\frac{2^{30}.3^{12}.5^{27}}{5^{28}.3^{14}.2^{29}}=\frac{2}{5.3^2}=\frac{2}{45}\)

f) \(\frac{25^2.20^4}{5^{10}.4^5}=\frac{\left(5^2\right)^5.\left(4.5\right)^4}{5^{10}.4^5}=\frac{5^{10}.5^4.4^4}{5^{10}.4^5}=\frac{5^{14}.4^4}{5^{10}.4^5}=\frac{5^4}{4}\)

i) \(\frac{9^{15}.81^4}{27^8.3^{20}}=\frac{\left(3^2\right)^{15}.\left(3^4\right)^4}{\left(3^3\right)^8.3^{20}}=\frac{3^{30}.3^{16}}{3^{24}.3^{20}}=\frac{3^{46}}{3^{44}}=3^2=9\)

f) Ta có: \(\frac{25^2.20^4}{5^{10}.4^5}\)= \(\frac{\left(5^2\right)^2.\left(4.5\right)^4}{5^{10}.4^5}\)= \(\frac{5^4.4^4.5^4}{5^{10}.4^5}\)= \(\frac{5^8.4^4}{5^{10}.4^5}\)= \(\frac{1}{5^2.4}\)=\(\frac{1}{100}\).

i) Ta có: \(\frac{9^{15}.81^4}{27^8.3^{20}}\)= \(\frac{\left(3^2\right)^{15}.\left(3^4\right)^4}{\left(3^3\right)^8.3^{20}}\)= \(\frac{3^{30}.3^8}{3^{24}.3^{20}}\)= \(\frac{3^{38}}{3^{44}}\)=\(\frac{1}{3^6}\)= \(\frac{1}{729}\)