Answer:
[tex]f(x) =4x^2 + 8x -2 \\f(x) = 4(x^2 + 2x -\frac{1}{2} )\\\\f(x) = 4(x^2 + 2x +1 - 1 -\frac{1}{2} )\\f(x) = 4((x+1)^2 - 1 -\frac{1}{2} ))\\f(x) = 4((x+1)^2 -\frac{3}{2} ))\\f(x) = 4(x+1)^2 -6\\[/tex]
the vertices (-1, -6)