Question 1204368
{{{ax^2+bx+c=0}}}

{{{general_solution}}} {{{x=(-b+- sqrt(b^2-4ac))/(2a)}}}

Your question is asking for {{{b^2-4ac}}} expression.


Your specific example is {{{(-4)^2-4*2(-30)}}} and you may compute this.
(The discriminant)