    Glossary Key Terms: axis of symmetry - dashed vertical line that contains the vertex completing the square - add a third term to a binomial to form a perfect square trinomial conjugates - radical expressions that differ only in the sign of one term discriminant - the portion under the radical sign irrational number - number that cannot be expressed as (a / b) where b is not equal to zero minimum/maximum point/value - point with the least/greatest value of the function perfect square - positive rational number whose principal square root is a rational number porabola - any equation in the form y = ax2 + bx + c has a graph that is a porabola principal square root - the positive square root of a positive real number quadratic function - an equation in the form y = ax2 + bx + c where a is not equal to zero radicand - number under the radical sign rational number - a real number that can be expressed in the form (a / b) where b is not equal to zero rationalize the denominator - multiply the numerator and the denominator by the least square root needed to make the radicand in the denominator a perfect square real number - aany number that is positive negative or zero right triangle - triangle with one angle with a degree measure of 90 subset - if all members of a set X are also members of set Y, then X is said to be a subset of Y vertex - turning point of a porabola 