Find the vertex and axis of symmetry of the graph of the function.
-$$f ( x ) = x ^ { 2 } - 6 x$$
A) (3, -9); x = 3
B) (9, -3); x = 9
C) (-9, 3); x = -9
D) (-3, 9); x = -3

Question

Quizplus · Accepted Answer

The vertex of a parabola in the form $f(x) = ax^2 + bx + c$ can be found using the formula $(- \frac{b}{2a}, f(- \frac{b}{2a}))$. For $f(x) = x^2 - 6x$, $a = 1$ and $b = -6$, so the x-coordinate of the vertex is $- \frac{-6}{2*1} = 3$. Plugging $x = 3$ into the function gives $f(3) = 3^2 - 6*3 = 9 - 18 = -9$, making the vertex (3, -9). The axis of symmetry is at $x = 3$.

Find the Vertex and Axis of Symmetry of the Graph f(x)=x2−6xf ( x ) = x ^ { 2 } - 6 xf(x)=x2−6x

Find the Vertex and Axis of Symmetry of the Graph $f ( x ) = x ^ { 2 } - 6 x$