The axis of symmetry of a parabola is a line about which the parabola is symmetrical.
When the parabola is vertical, the line of symmetry is vertical.
When a quadratic function is graphed in the coordinate plane, the resulting parabola and corresponding axis of symmetry are vertical.
The graph of the parabola represented by the quadratic function y = a( x - p )2 + q has an axis of symmetry represented by the equation of the vertical line x = p.
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