Final answer:
The domain of all quadratic functions is (-∞, +∞), while the range is determined by the vertex.
Step-by-step explanation:
The domain of all quadratic functions is (-∞, +∞). This means that the x-values the quadratic function can take are any real numbers. The reason for this is that a quadratic function is a polynomial function of degree 2, and polynomials have a domain of (-∞, +∞).
The range of a quadratic function is determined by the vertex. The vertex of a quadratic function is the highest or lowest point on the graph, depending on whether the parabola opens upwards or downwards. The range of a quadratic function is the set of all y-values that can be obtained by plugging in the x-values from the domain into the function.
So the correct answer is:
a) The leading coefficient of a quadratic function is always 1.
b) The vertex of the quadratic equation.