Set 15: Quadratic Equations (Advanced)

Choice B is correct. Choice B is the correct answer. Always factor out the GCF first. 1. Factor out 2: $2(x^2 - 9)$. 2. Recognize that $x^2 - 9$ is a difference of squares. 3. Factor $x^2 - 9$ into $(x - 3)(x + 3)$. Final answer: $2(x - 3)(x + 3)$. Choice A is incorrect because $(x-3)^2$ expands to $x^2 - 6 x + 9$, which has a middle term. Choice C is incorrect because while mathematically equivalent, it is not completely factored (the first factor $2x-6$ still has a GCF of 2). Choice D is incorrect because it doesn't expand to the original expression.