Question

решите).........'.'''..'...

Answer 1

$a\ne 0\\\\a^{20}=(a^4)^5\\\\a^{20}=(a^{-5})^{-4}\\\\a^{20}=(\frac{1}{a^2})^{-10}\\\\a^{20}=(a^4)^5=(\frac{1}{a^{-4}})^{5}$