Question 331974
In a quadratic equation, the discriminant is that quantity that appears under the radical sign of the quadratic formula.
Here's the quadratic formula: {{{x = (-b+-sqrt(b^2-4ac))/2a}}}
The discriminant is: {{{b^2-4ac}}} and, for your problem, this would be:
{{{10^2-4(15)(-1)}}} and when this is evaluated, it is:
{{{100-(-60) = 160}}}
The discriminant is a positive quantity, the the quadratic equation will have two real roots.
Notice that the discriminant does not conain a variable, as you have shown in your answer!