The number of positive real roots of the equation $$3^{x+1}+3^{-x+1}=10$$ is

The number of real roots of the equation $$\sqrt{\frac{x}{1-x}}+\sqrt{\frac{1-x}{x}}=\frac{13}{6}$$ is

For $$a\ne b$$, if the equation $$x^2+ax+b=0$$ and $$x^2+bx+a=0$$ have a common root, then the value of $$a+b$$ is equal to

If the product of the roots of $$9x^3+112x^2-120x+a=0$$ is 12, then the value of $$a$$ is