Question 1084987
the discriminant is b^2 - 4ac.


that's the expression within the square root sign of the quadratic formula.


if the discriminant is 0, then you have 1 real solution.


if the discriminant is negative, then you have 2 complex solutions (not real).


if the discriminant is positive, then you have 2 real solutions.


if the discriminant is positive and a perfect square, then you have 2 real solutions that are rational.


here's a couple of references.


<a href = "http://www.mathwords.com/d/discriminant_quadratic.htm" target = "_blank">http://www.mathwords.com/d/discriminant_quadratic.htm</a>


<a href = "http://www.purplemath.com/modules/quadform2.htm" target = "_blank">http://www.purplemath.com/modules/quadform2.htm</a>