![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
tìm số nguyên dương n thỏa mãn:
[tex]\LARGE 3^{2n}C_{2n+1}^{1}-2.2.3^{2n-1}C_{2n+1}^{2}+3.2^{2}.3^{2n-2}C_{2n+1}^{3}-...+(2n+1).2^{2n}.C_{2n+1}^{2n+1}=4031[/tex]
[tex]\LARGE 3^{2n}C_{2n+1}^{1}-2.2.3^{2n-1}C_{2n+1}^{2}+3.2^{2}.3^{2n-2}C_{2n+1}^{3}-...+(2n+1).2^{2n}.C_{2n+1}^{2n+1}=4031[/tex]