Question 78030
(7 cube 3√15 c^8 d^4)(3 cube 3√75 c^5 d^4) 
(7^3*3sqrt(15)*c^8*d^4)(3^3*3sqrt(75)*c^5*d^4)
= (7*3)^3*(9sqrt(15*75))*(c^(8+5))*(d^(4+4))
= 9261*(9*15sqrt3)*c^13*d^8
=125235(sqrt3) c^13 d^8
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Cheers,
Stan H.