AMC12 2005 A

AMC12 2005 A · Q9

AMC12 2005 A · Q9. It mainly tests Quadratic equations, Vieta / quadratic relationships (basic).

There are two values of $a$ for which the equation $4x^2 + ax + 8x + 9 = 0$ has only one solution for $x$. What is the sum of those values of $a$?

方程 $4x^2 + ax + 8x + 9 = 0$ 只有一个 $x$ 解时，$a$ 有两个取值。这两个 $a$ 值的和是多少？

(A) -16 -16

(B) -8 -8

(C) 0 0

(D) 8 8

(E) 20 20

Answer

Correct choice: (A)

正确答案：（A）

Solution

https://youtu.be/3dfbWzOfJAI?t=222

https://youtu.be/3dfbWzOfJAI?t=222

Topics

AL.005 Quadratic equations AL.014 Vieta / quadratic relationships (basic)

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