Answer
78
Work Step by Step
$(4\sqrt{5}+\sqrt2)(4\sqrt{5}-\sqrt2)$
Use the FOIL method to multiply the binomial.
Multiply the First terms, the Outside terms, the Inside terms, and the Last terms.
$(4\sqrt{5}\times4\sqrt{5})+(4\sqrt5\times(-\sqrt2))+(4\sqrt5\times\sqrt2)+(\sqrt2\times(-\sqrt2))$
Simplify.
$80-4\sqrt{10}+4\sqrt{10}-2$
Combine like terms/like radicals.
$78$
