Could be the equation for a parabola that opens down with vertex (-11 -28)?

The equation of a parabola that opens downward can be expressed in vertex form as ( y = a(x - h)^2 + k ), where ((h, k)) is the vertex. For a vertex at (-11, -28), the equation becomes ( y = a(x + 11)^2 - 28 ). The value of ( a ) must be negative to ensure the parabola opens downward. For example, if ( a = -1 ), the equation would be ( y = -(x + 11)^2 - 28 ).