Set 10: Quadratic Equations (Advanced)

Choice A is correct. Choice A is the correct answer. According to Vieta's formulas, for $ax^2 + bx + c = 0$: 1. Sum of roots = $-b/a$. 2. Substitute $a=2, b=-8$: Sum = $-(-8)/2$. 3. Simplify: $8 /2 = 4$. Choice B is incorrect because of sign error. Choice C is incorrect because it is the product ($c/a$). Choice D is incorrect because it forgets to divide by $a$.