<PRE><B>Question 873460</B>
FOIL Method:
First:{{{ (5*sqrt(30))(4*sqrt(42))=20*sqrt(1260)=120*sqrt(35)}}}
Outer:{{{ (5*sqrt(30))(-3*sqrt(105))=-15*sqrt(3150)=-225*sqrt(14)}}}
Inner:{{{ (-7*sqrt(70))(4*sqrt(42))=-28*sqrt(2940)=-392*sqrt(15)}}}
Last:{{{ (-7*sqrt(70))(-3*sqrt(105))=21*sqrt(7350)=735*sqrt(6)}}}
Add it up.
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{{{ (5sqrt(30)-7sqrt(70))(4sqrt(42)-3sqrt(105))=120sqrt(35)-225sqrt(14)-392sqrt(15)+35sqrt(6)}}}
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