25. What is the product of the real roots of the equation
$$
\frac{x^{2}+90 x+2027}{3}=\sqrt{x^{2}+90 x+2055} ?
$$
25. Ans: 2006.
Let $u=\sqrt{x^{2}+90 x+2055}$. Then $u^{2}-28=3 u$. Solve to find the positive root $u=7$. Hence $x^{2}+90 x+2006=0$, so the product of the real roots is 2006 .