Chapter 4 - Quadratic Functions and Equations - 4-5 Quadratic Equations - Practice and Problem-Solving Exercises - Page 231: 64

$(4x-1)(4x+1)$

Note that: $16x^2=(4x)(4x)=(4x)^2$ $1=1^2$ Thus, the given expression is equivalent to: $(4x)^2-1^2$ Recall: $a^2-b^2=(a-b)(a+b)$ Factor the expression using the formula above with $a=4x$ and $b=1$ to obtain: \begin{align*} (4x)^2-1^2&=(4x-1)(4x+1) \end{align*}