if i am asked roots of equation for ax^2+bx+c=0 which formula is this, it may seem easy but i not sure what asking
If $\displaystyle a\not = 0$ and let $\displaystyle \Delta = b^2 - 4ac$.
If $\displaystyle \Delta >0$ the roots are $\displaystyle \frac{-b+\sqrt{\Delta}}{2a},\frac{-b-\sqrt{\Delta}}{2a}$
If $\displaystyle \Delta = 0$ there is just one root $\displaystyle -\frac{b}{2a}$
If $\displaystyle \Delta < 0$ the roots are $\displaystyle \frac{-b+i\sqrt{-\Delta}}{2a}, \frac{-b-i\sqrt{-\Delta}}{2a}$. Where $\displaystyle i$ is defined to be so that $\displaystyle i^2 = -1$.
You should use the quadratic formula for the roots.
RonL