Question 442759
Perform the multiplication and simplify, if possible 
9 sqrt(3) (8 sqrt (5) + 6 sqrt (7)) 
options are 
54 sqrt (15) + 72 sqrt (21)
72 sqrt (15) + 54 sqrt (21)
54 sqrt (3) + 72 sqrt (7)
72 sqrt (3) + 54 sqrt (7)
72 sqrt (5) + 54 sqrt (7) 
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9 sqrt(3)*(8 sqrt (5) + 6 sqrt (7)) 
Just multiply it.  Multiply what's outside and inside the radicals separately.
= 9*8*sqrt(3*5) + 9*6*sqrt(3*7)
= 72sqrt(15) + 54sqrt(21)