# ACT® Math

Free Version
Moderate

ACTMAT-EF4GOH

For which real value of $x$ is $f(x)$ the greatest if:

$$f(x) = ax^2 + bx + c$$

...(where $a < 0$) the greatest?

A

$-\cfrac{b}{2a}$

B

$-\cfrac{b}{a}$

C

$\sqrt { { b }^{ 2 }-4ac }$

D

$b^2-4ac$

E

$\cfrac { -b\pm \sqrt { b^{ 2 }-4ac } }{ 2a }$