Find the vertex and axis of symmetry of the graph of the function.
-$$f ( x ) = - 8 x ^ { 2 } - 2 x - 4$$
A) $\left( - 8 , - \frac { 31 } { 8 } \right) ; x = - 8$
B) $\left( \frac { 1 } { 8 } , \frac { 31 } { 8 } \right) ; x = \frac { 1 } { 8 }$
C) $( 8 , - 4 ) ; x = 8$
D) $\left( - \frac { 1 } { 8 } , - \frac { 31 } { 8 } \right) ; x = - \frac { 1 } { 8 }$

Question

Quizplus · Accepted Answer

The vertex of a parabola given by $f(x) = ax^2 + bx + c$ can be found using the formula $x = -\frac{b}{2a}$. For the given function, $a = -8$ and $b = -2$, so $x = -\frac{-2}{2(-8)} = -\frac{1}{8}$. Plugging this back into the function gives the y-coordinate of the vertex. The axis of symmetry is the x-value of the vertex, hence $x = -\frac{1}{8}$.

Find the Vertex and Axis of Symmetry of the Graph f(x)=−8x2−2x−4f ( x ) = - 8 x ^ { 2 } - 2 x - 4f(x)=−8x2−2x−4

Find the Vertex and Axis of Symmetry of the Graph $f ( x ) = - 8 x ^ { 2 } - 2 x - 4$