Fill in the Blank with One of the Words or Phrases

Multiple Choice

Fill in the blank with one of the words or phrases listed below. $$\begin{array} { l l l l } \text { quadratic formula } & \text { quadratic } & \text { discriminant } & \pm \sqrt { b } \\\text { completing the square } & \text { quadratic inequality } & ( h , k ) & ( 0 , k ) \\( h , 0 ) & \frac { - b } { 2 a } & &\end{array}$$
-A ______equation is one that can be written in the form $a x ^ { 2 } + b x + c = 0$ where $a , b$ , and $c$ are real numbers and a is not 0 .

A) discriminant
B) quadratic
C) completing the square
D) quadratic formula