#### Answer

-37

#### Work Step by Step

$(2\sqrt{3}+7)(2\sqrt{3}-7)$
Use the FOIL method to multiply the binomial.
Multiply the First terms, the Outside terms, the Inside terms, and the Last terms.
$(2\sqrt{3}\times2\sqrt{3})+(-7\times2\sqrt3)+(7\times2\sqrt3)+(7\times(-7))$
Simplify.
$12-14\sqrt{3}+14\sqrt{3}-49$
Combine like terms/like radicals.
$-37$