The graph of a quadratic function is a parabola. The axis of symmetry of a parabola is a vertical line that divides the parabola into two congruent halves. The axis of symmetry always passes through the vertex of the parabola. The x coordinate of the vertex is the equation of the axis of symmetry of the parabola. Taking into account the definition above, then the other intersection with x will be: horizontal distance between the axis of symmetry and intersection with x: d = 7 - (- 1) = 7 + 1 = 8 The second intersection will then be: x2 = -1-8 = -9
