Set 14: Quadratic Equations

Choice A is correct. Choice A is the correct answer. For one solution, $\Delta = 0$. 1. $b^2 - 4(1)(25) = 0$. 2. $b^2 - 100 = 0$. 3. $b^2 = 100$. 4. $b = \pm 10$. Choice B is incorrect because it misses the negative case. Choice C is incorrect because it uses $\sqrt{25}$. Choice D is incorrect because it uses $\sqrt{25}$.