Answer:
Step-by-step explanation:
The relevant rule of exponents is ...
(a^b·c^d)^e = a^(be)·c^(de)
Then ...
(m^(5/4)·n^(-4/5))^(7/3) = m^(5/4·7/3)·n^(-4/5·7/3)
= m^(35/12)·n^(-28/15)
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Since you want positive rational exponents, you can write this as ...
= m^(35/12)/n^(28/15)