The first part of the quadratic formula, x = - b/2a, is the equation of the axis of symmetry, and the x-coordinate of the vertex.
In standard form: - 2x² + 8x - 5 = 0, a = - 2, b = 8, c = - 5
The axis of symmetry: x = - 8/2(- 2) = - 8/- 4 = 2
Go back and solve for y to find the y-coordinate of the vertex.
y = - 2(2)² + 8(2) - 5
y = - 2(4) + 16 - 5
y = - 8 + 16 - 5
y = 3
Vertex is (2, 3)
