First write out your original equation. [tex] {(\frac{ {4}^{7} }{ {5}^{2} } ) }^{3} [/tex] Then use the law of exponents(power of a power) to simplify. [tex] \frac{ {4}^{21} }{ {5}^{6} } [/tex] (Multiply the numerator and denominator exponents by the outside power.)