The shape of a is a .
Since the shape of this graph is a line, not a parabola, the function is not quadratic.
The graph of the function is a parabola and, thus, the function is a quadratic function.
The function is a curve, not a parabola. This means that the function is not a quadratic function.
A can both be faced upward or downward.
Therefore, this is a quadratic function.