Question

What is the vertex A,B,C or D

Answer 1

(C) (-2, -36) . . . . . . is the appropriate choice

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An easy way to tell is to let a graphing calculator show you.

Or, you can rearrange the equation to vertex form.
  f(x) = 5(x² +4x) -16
    = 5(x² +4x +4) -16 -5*4 . . . . complete the square
    = 5(x +2)² -36
So, the vertex is (-2, -36).