we know that
The formula to solve a quadratic equation of the form \(ax^{2} +bx+c=0\) is equal to
\(x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}\)
the discriminant is equal to \({b^{2}-4ac\)
in this problem we have
\(-3=-x^{2} +2x\)
\(x^{2}-2x-3=0\)
so
\(a=1\\b=-2\\c=-3\)
substitute the values
\({(-2)^{2}-4(1)(-3)=4+12=16\)
therefore
the answer is
\(16\)
