If we write the equation in the form $$\frac{1}{2}at^2+ut-s=0$$ and assuming $a\
e 0$ using the quadratic formula $$x=\frac{-B\pm\sqrt{B^2-4AC}}{2A}$$ where `A`, `B` and `C` relate to $$Ax^2+Bx+C=0$$ we get $$A=\frac{1}{2}a$$ $$B=u$$ $$C=-s$$ $$t_{1,2}=\frac{-u\pm\sqrt{u^2+2as}}{a}$$