Giải thích các bước giải:
Bài 4:
q.$\dfrac{9^{14}.25^5.8^7}{18^{12}.625^3.24^3}$
$=\dfrac{(3^2)^{14}.(5^2)^5.(2^3)^7}{(2.3^2)^{12}.(5^4)^3.(2^3.3)^3}$
$=\dfrac{3^{28}.5^{10}.2^{21}}{2^{12}.3^{24}.5^{12}.2^9.3^3}$
$=\dfrac{3^{28}.5^{10}.2^{21}}{2^{12+9}.3^{24+3}.5^{12}}$
$=\dfrac{3^{28}.5^{10}.2^{21}}{2^{21}.3^{27}.5^{12}}$
$=\dfrac{3}{5^{2}}$
$=\dfrac{3}{25}$