
6.6.17 Combinatorics
Problem:
Find the coefficients when
\[
a=x^{2} \cdot y^{4} \cdot z^{3}, b=x^{2} \cdot y^{3} \cdot z, c=x^{4} \cdot z^{4}
\]
in the expansion \( \left(5 \cdot x^{2}+3 \cdot y^{2}+2 \cdot z\right)^{6} \).