Question

Find the axis of symmetry of the graph y = x2 + 8x + 16.

Answer 1

The axis of simetry of a parabola is the vertical line that cross the vertex of the parabola.

So, we need to find the x-value of the vertex:

`\begin{gathered} \text{The general equation of a parabola is:} \\ y=ax^2+bx+c \\ \text{The x-value of the vertex is:} \\ x_v=-(b)/(2a) \end{gathered}`

So, in this case a=1 and b=8:

`x_v=-(8)/(2\cdot1)=-4_{}`

The axis of simetry is x=-4.