[tex] x^2-2x-3=0\\\\a=1;\ b=-2;\ c=-3\\\\x=\dfrac{-(-2)\pm\sqrt{(-2)^2-4(1)(-3)}}{2(1)}\\\\\boxed{x=\dfrac{2\pm\sqrt{(-2)^2-4(1)(-3)}}{2(1)}}\to\text{first answer} [/tex]
