Question 1063292
If you mean
sqrt(3y^4u^9)*sqrt(15y^2u^4)
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Multiply them.
= sqrt(45y^6u^13)
= sqrt(9y^6u^12*5u)
= sqrt(9y^6u^12)*sqrt(5u)
= 3y^3u^6*sqrt(5u)
= {{{3y^3u^6*sqrt(5u)}}}