Chapter 6 - Radical Functions and Rational Exponents - 6-3 Binomial Radical Expressions - Practice and Problem-Solving Exercises - Page 380: 69

$13$

Use the FOIL method to expand: $(5)(5) + (5)(2\sqrt {3}) + (-2\sqrt {3})(5) + (-2\sqrt {3})(2\sqrt {3})$ Multiply to simplify: $25 + 10\sqrt {3} - 10\sqrt {3} - 4\sqrt {9}$ Simplify radicals: $25 + 10\sqrt {3} - 10\sqrt {3} - 4 \cdot 3$ Multiply to simplify: $25 - 12$ Combine like terms: $13$