Hi
y= 2x^2-4x -16
Note: the vertex form of a parabola,where(h,k) is the vertex
y= 2x^2-4x -16 |Completing the square
y = 2[(x-1)^2 - 1] -16
y = 2(x-1)^2 - 2 -16
y = 2(x-1)^2 -18 Vertex(1,-18) a = 2 > 0 parabola opens upward
Line of symmetry is x = 1
x-intercepts when y = 0 are also the solutions for the quadratic equation
2(x-1)^2 = 18
x-1 = ±
x = 1 ± 3 x = 4 or x = -2