Background
A quadratic function has a Ushaped graph called a
parabola. A quadratic function can be written in the
form ax^{2} + c, where a is called the leading coefficient.
If a is positive, the parabola opens up.
If a is negative, the parabola opens down. If the
absolute value of a is greater than 1, then the
parabola will be narrower than y = x^{2}. If the
absolute value of a is less than 1, then the parabola
will be wider than y = x^{2}.
The vertex of a parabola is the point from which the
graph opens up or down.
Adding values to and subtracting values from ax^{2}
translates the vertex along the yaxis.
In the form y = (x  a)(x  b), the vertex is
located at (a, b) . 
WarmUp
matches
.
The vertex is at (0, 4). Because the leading
coefficient is positive, the graph opens up. Because
the leading coefficient is less than 1, the graph will
be wider than y = x^{2}.
