I am stuck at a question after trying a lot,plzz help me

Q. If the equation $\dfrac{x^2}{(1+x^2)^2}+\dfrac{ax}{1+x^2}+3=0$

has two real and distinct roots then a lies in the interval $(-\infty,a)\cup(b,\infty)$.

Then find the value of $\displaystyle{\frac{a+b}{13}}$?.