In $\mathrm{\Delta ABC}$, right angled at A,  in radius,  circum radius,  and radius of the Excircle opposite to A are respectively in the ratio 2:5: $\mathrm{\lambda }$, then the roots of the equation ${\mathrm{x}}^2-\left(\mathrm{\lambda }-8\right)\mathrm{x}+\left(\mathrm{\lambda }-9\right)=0$