2項展開の応用

定数項は
$$\begin{array}{rl}& {}_5{C}_5(-2{)}^5+{}_5{C}_1\cdot {}_4{C}_1\cdot {}_3{C}_3{x}^1{(-\frac{3}{x})}^1(-2{)}^3+{}_5{C}_2\cdot {}_3{C}_2\cdot {}_1{C}_1{x}^2{(-\frac{3}{x})}^2(-2{)}^1\\ & =-32+480–540\\ & =-92\end{array}$$