## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

Published by Pearson

# Chapter 10 - Exponents and Radicals - Review Exercises: Chapter 10: 55

#### Answer

$29$

#### Work Step by Step

Using the product of the sum and difference of like terms which is given by $(a+b)(a-b)=a^2-b^2,$ the given expression is equivalent to \begin{array}{l}\require{cancel} (2+5i)(2-5i) \\\\= (2)^2-(5i)^2 \\\\= 4-25i^2 .\end{array} Using $i^2=-1,$ the expression above is equivalent to \begin{array}{l}\require{cancel} 4-25i^2 \\\\= 4-25(-1) \\\\= 4+25 \\\\= 29 .\end{array}

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