Chapter 6 - Radical Functions and Rational Exponents - 6-4 Rational Exponents - Practice and Problem-Solving Exercises - Page 388: 105

$-7$

We're going to use the FOIL method to multiply the two binomials. With the FOIL method, we multiply the first terms first, then the outer terms, then the inner terms, and, finally, the last terms: $=1(1) + 1(2\sqrt 2) - 1(2\sqrt 2) - (2\sqrt 2)(2\sqrt 2)$ Simplify to obtain:: $=1 + 2\sqrt 2 - 2\sqrt 2 - 4\sqrt 4$ $=1 - 4\sqrt 4$ $=1 - 4(2)$ $=1 - 8$ $=-7$