Answer
$4x^{2} - 49$
Work Step by Step
We use the formula for the difference of squares to apply to this question.
The difference of squares formula is:
$(a-b) (a+b) = a^{2} - b^{2}$
In the given formula let 2x represents a and 7 represents b.
$(2x-7) (2x+7) = (2x)^{2} - (7)^{2}$
= $4x^{2} - 49$
