Set 5: Quadratic Equations (Intermediate)

Choice C is correct. Choice C is the correct answer. This is a difference of squares: $(4 x)^2 - 1^2$. 1. $a = 4 x$, $b = 1$. 2. Formula: $(a - b)(a + b)$. 3. Result: $(4 x - 1)(4 x + 1)$. Choice A is incorrect because it would have a middle term of $-8 x$. Choice B is incorrect because it expands to $16x^2 + 15 x - 1$. Choice D is incorrect because it expands to $16x^2 + 6 x - 1$.