If $m$ and $M$ are respectively, the smallest and greatest rational roots of the equation $6 x^6-25 x^5+31 x^4-31 x^2+25 x-6=0$, then $M-m=$

If $\alpha$ and $\beta$ are the roots of the equation $x^2-2 \sqrt{3} x+4=0$, then $\alpha^6+\beta^6=$

When $b=17$, it is found that the roots of the equation $x^2+b x+c=0$ are -2 and -15 . If $\alpha$ and $\beta$ are the roots of the same equation when $b=13$, then $|\alpha-\beta|=$

Let $x$ be a real number. Malch the following:

$$ \text { The correct match is : } $$