Answer:
(a, b) ∈ {(1, 729), (3, 243), (9, 81), (27, 27), (81, 9), (243, 3) (729, 1)}
Step-by-step explanation:
[tex]\sqrt{a\cdot b}=27\\\\(\sqrt{a\cdot b})^2=27^2\\\\a\cdot b=729\\\\\\729=27\cdot27=9\cdot81=3\cdot243=1\cdot729[/tex]
So:
(a, b)∈{(1, 729), (3, 243), (9, 81), (27, 27), (81, 9), (243, 3) (729, 1)}