This quadratic function is in vertex form, which is
y = a(x - h)^2 + k, where (h, k) is the vertex of the graph of the function. Also, if a >0, the parabola will open upward and the y-coordinate of the vertex will be the minimum value of the curve. If a <0, the parabola will open downward and the y-coordinate of the vertex will be the maximum value of the curve.
In y = -2(x + 5)^2 - 8, a = -2 and -2 < 0, so the parabola will open downward and the maximum value of the curve will be the y-coordinate of the vertex, or k. In this equation, k = -8, so the maximum valu of the function is -8.
