Set 15: Quadratic Equations

Choice A is correct. Choice A is the correct answer. 1. Take the square root of both sides: $x - 1 = \pm \sqrt{5}$. 2. Add 1 to both sides to isolate x: $x = 1 \pm \sqrt{5}$. This represents two irrational solutions: $1+ \sqrt{5}$ and $1- \sqrt{5}$. Choice B is incorrect because of a sign error (subtracted 1 instead of adding). Choice C is incorrect because it adds 1 inside the radical, which is invalid. Choice D is incorrect because it swaps the order of operations.