Find the vertex of the parabola.
-$$f ( x ) = - 2 x ^ { 2 } - 20 x - 54$$
A) $( 4,5 )$
B) $( - 5 , - 4 )$
C) $( - 4 , - 5 )$
D) $( 5,4 )$

Question

Quizplus · Accepted Answer

The vertex of a parabola in the form $f(x) = ax^2 + bx + c$ is given by the formula $(-b/2a, f(-b/2a))$. Here, $a = -2$ and $b = -20$. So, the x-coordinate of the vertex is $-(-20)/(2 \times -2) = -5$. Plugging $x = -5$ into the function gives the y-coordinate: $f(-5) = -2(-5)^2 - 20(-5) - 54 = -4$. Thus, the vertex is $(-5, -4)$.

Find the Vertex of the Parabola f(x)=−2x2−20x−54f ( x ) = - 2 x ^ { 2 } - 20 x - 54f(x)=−2x2−20x−54

Find the Vertex of the Parabola $f ( x ) = - 2 x ^ { 2 } - 20 x - 54$