The first three steps in writing f(x) = 40x 5x2 in vertex form are shown. Write the function in standard form.f(x) = 5x2 40x Factor a out of the first two terms.f(x) = 5(x2 8x) Form a perfect square trinomial.(eight-halves) squared = 16 f(x) = 5(x2 8x 16) – 5(16) What is the function written in vertex form? f(x) = 5(x 4) – 80 f(x) = 5(x 8) – 80 f(x) = 5(x 4)2 – 80 f(x) = 5(x 8)2 – 80