Question 210191
{{{-x^2-x=4}}} Start with the given equation.



{{{-x^2-x-4=0}}} Subtract 4 from both sides.



From {{{-x^2-x-4}}} we can see that {{{a=-1}}}, {{{b=-1}}}, and {{{c=-4}}}



{{{D=b^2-4ac}}} Start with the discriminant formula.



{{{D=(-1)^2-4(-1)(-4)}}} Plug in {{{a=-1}}}, {{{b=-1}}}, and {{{c=-4}}}



{{{D=1-4(-1)(-4)}}} Square {{{-1}}} to get {{{1}}}



{{{D=1-16}}} Multiply {{{4(-1)(-4)}}} to get {{{(-4)(-4)=16}}}



{{{D=-15}}} Subtract {{{16}}} from {{{1}}} to get {{{-15}}}



So the discriminant is -15.