Question 73878
radical (7) (2radical(3) + 3 radical (7) )
The rule for multiply radicals is (sqrt(a))(sqrt(b))=sqrt(ab)
Your problem:
= [2(sqrt(7)*sqrt(3)] +[(sqrt(7)*(3sqrt7)]

=[2sqrt(21) + 3*7]

=2sqrt21 + 21 

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Cheers,
Stan H.