8 In $\triangle A B C$, the sides opposite to angles $A, B, C$ are $a, b, c$ respectively, and $b \neq 1$. Also, $\frac{C}{A}, \frac{\sin B}{\sin A}$ are the roots of the equation $\log _{\sqrt{b}} x=\log _{b}(4 x-4)$. Then the shape of $\triangle A B C$ is $\qquad$
8 A non-isosceles right triangle. Hint: From $\log _{\sqrt{b}} x=\log _{b}(4 x-4)$ we get $x=2$, so
$$
\left\{\begin{array} { l } 
{ C = 2 A , } \\
{ \sin B = 2 \sin A , } \\
{ A + B + C = \pi }
\end{array} \Rightarrow \text { in } \triangle A B C \text { only } \left\{\begin{array}{l}
A=\frac{\pi}{6}, \\
C=\frac{\pi}{3}, \\
B=\frac{\pi}{2} .
\end{array}\right.\right.
$$
(Supplied by Ran Chongjing, No. 1 High School of Urumqi)