Chapter 9 - Cumulative Review - Page 677: 26

$(2x-1+3y)(2x-1-3y)$

$4x^2-4x+1-9y^2$ $4x^2-2x-2x+1-9y^2$ $(4x^2-2x)-(2x-1)-9y^2$ $2x(2x-1)-1(2x-1)-9y^2$ $(2x-1)(2x-1)-9y^2$ $(2x-1)^2-9y^2$ Let $z=2x-1$ $(2x-1)^2-9y^2$ $z^2-9y^2$ $(z+3y)(z-3y)$ $(z+3y)(z-3y)$ $(2x-1+3y)(2x-1-3y)$