Question 603655
ab^9=15

ab^6=42
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ab^9/ab^6 = 15/42
b^3 = 5/14
{{{b = root(3,5/14))}}}
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ab^6 = 42
a = 42/b^6 = 42/(5/14)^2 = 42/(25/196)
a = 42*196/25