4. If $x_{1}, x_{2}, x_{3}, x_{4}, x_{5}$ satisfy the following system of equations
$$
\cdot\left\{\begin{array}{c}
2 x_{1}+x_{2}+x_{3}+x_{4}+x_{5}=6, \\
x_{1}+2 x_{2}+x_{3}+x_{4}+x_{5}=12, \\
x_{1}+x_{2}+2 x_{3}+x_{4}+x_{5}=24, \\
x_{1}+x_{2}+x_{3}+2 x_{4}+x_{5}=48, \\
x_{1}+x_{2}+x_{3}+x_{4}+2 x_{5}=96
\end{array}\right.
$$

Find: $3 x_{4}+2 x_{5}$.
4. Adding up the 5 equations, and then dividing both sides by 6, we get:
$$
x_{1}+x_{2}+x_{3}+x_{4}+x_{5}=31 .
$$

By subtracting (1) from the 4th and 5th equations respectively, we obtain
$$
x_{4}=17, x_{5}=65 \text {, }
$$

Therefore, $3 x_{4}+2 x_{5}=51+130=181$.