Final answer:
If the leading coefficient of a quadratic function is negative, then the parabola opens downwards.
Step-by-step explanation:
If the leading coefficient of a quadratic function is negative, then the parabola opens downwards. This means that the vertex of the parabola is the highest point on the curve.
For example, consider the quadratic function y = -x^2. The graph of this function is a downward-opening parabola and the vertex is at the point (0, 0).
Similarly, for any quadratic function with a negative leading coefficient, the parabola will always open downwards.