Question

Given the vertex of the parabola, how can you determine the equation of the line of symmetry?

Answer 1

To find the line of symmetry algebraically, you need to identify if the equation is written in standard form or vertex form. Standard form is y = ax^2 + bx + c, where a, b, and c equal all real numbers. You can use the formula x = -b / 2a to find the line of symmetry. Vertex form is y = (x - h)^2 + k.

Answer 2

This vertical line, right through the vertex, is called the axis of symmetry. If you're asked for the axis, write down the line "x = h", where h is just the x-coordinate of the vertex. So in the example above, then the axis would be the vertical line x = h = –1/6.