## Intermediate Algebra (6th Edition)

Published by Pearson

# Chapter 11 - Section 11.4 - Partial Sums of Arithmetic and Geometric Sequences - Exercise Set - Page 660: 55

#### Answer

$8x^3-12x^2+6x-1$

#### Work Step by Step

Using $(a+b)^3=a^3+3a^2b+3ab^2+b^3$ (or the cube of a binomial), the given expression, $(2x-1)^3 ,$ is equivalent to \begin{array}{l}\require{cancel} (2x)^3+3(2x)^2(-1)+3(2x)(-1)^2+(-1)^3 \\\\= 8x^3+3(4x^2)(-1)+3(2x)(1)-1 \\\\= 8x^3-12x^2+6x-1 .\end{array}

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