Answer:
Below in bold.
Step-by-step explanation:
y = -4x2 + 8x - 13
Divide first 2 terms by -4:-
y = -4(x^2 - 2x) - 13
Convert to vertex form by completing the square:
y = -4[(x - 1)^2 - 1] - 13
y = -4(x - 1)^2 + 4 - 13
y = -4(x - 1)^2 - 9 <---------- Vertex form
y = a(x - j)^2 + k <---------- General form with vertex = (j, k).
So comparing, we see that the vertex is (1, -9).
