#### Answer

$-93-36\sqrt7$

#### Work Step by Step

$(6-3\sqrt7)(2-5\sqrt7)$
Use the FOIL method to multiply the binomial.
Multiply the First terms, the Outside terms, the Inside terms, and the Last terms.
$(6\times2)+(6\times(-5)\sqrt7)+(2\times(-3)\sqrt7)+((-3)\sqrt7\times(-5)\sqrt7)$
Simplify.
$12-30\sqrt7-6\sqrt7-105$
Combine lik terms/like radicals.
$-93-36\sqrt7$