Problem - 3667
If $abc=1$, solve this equation $$\frac{2ax}{ab+a+1}+\frac{2bx}{bc+b+1}+\frac{2cx}{ca+c+1}=1$$
Because
$$\frac{2ax}{ab+a+1} = \frac{2ax}{ab+a+abc}=\frac{2x}{b+1+bc}$$
$$\frac{2cx}{ca+c+1} = \frac{2bcx}{cab+bc+b}=\frac{2bcx}{1+bc+b}$$
\begin{align*}
\implies 1 &= \frac{2ax}{ab+a+1}+\frac{2bx}{bc+b+1}+\frac{2cx}{ca+c+1} \\
&= \frac{2x}{b+1+bc}+ \frac{2bx}{bc+b+1}+\frac{2bcx}{1+bc+b}\\
&= \frac{2x(1+b+bc)}{bc+b+1}\\
&= 2x
\end{align*}
$$\therefore\quad x=\boxed{\frac{1}{2}}$$