## Algebra: A Combined Approach (4th Edition)

Answer: $4x^{2}$ -1
(2x + 1)(2x - 1) This can be put in a generalized statement: (a + b)(a - b) = $a^{2} - b^{2}$. Comparing the statement wth our expression, a = 2x and b = 1. Thus, (2x + 1)(2x - 1) = $(2x)^{2} - 1^{2}$ = $4x^{2}$ -1.