1. Find the sum of all roots of the following equation:
$$
\sqrt[4]{x}=\frac{12}{7-\sqrt[4]{x}}
$$
1. Let $y=\sqrt[4]{x}$, then the original equation can be transformed into $y^{2}-7 y+12=0$, whose roots are 3 and 4, so the solution is $s^{4}+4^{4}$ $=337$.