[tex]\text{Use:}\\\\\left(\dfrac{a}{b}\right)^n=\dfrac{a^n}{b^n}\\\\(a\cdot b)^n=a^n\cdot b^n\\\\(a^n)^m=a^{nm}\\\\......................................................\\\\\left(\dfrac{m^5n}{pq^2}\right)^4=\dfrac{(m^5n)^4}{(pq^2)^4}=\dfrac{(m^5)^4n^4}{p^4(q^2)^4}=\dfrac{m^{20}n^4}{p^4q^8}[/tex]