## Introductory Algebra for College Students (7th Edition)

$$(2x - 7)(2x + 7)$$
On observation, we can see that this expression is the difference of two squares. The form for expressions written as the difference of two cubes is: $$(A - B)(A + B)$$ where $A$ is the square root of the leading term and $B$ is the square root of the last term. In this problem, we have $A$ as $\sqrt (4x^2)$ or $2x$ and $B$ as $\sqrt 49$ or $7$. We plug these values into the formula: $$(2x - 7)(2x + 7)$$