Find the 4th term from the end in the expansion of (4x/5-5/2x)^9

Question

Find the 4^th term from the end in the expansion of \(\Big(\frac{4x}{5}-\frac{5}{2x}\Big)^9\)

Answer 1

To Find : 4^th term from the end 

Formulae :

As n=9, therefore there will be total (9+1)=10 terms in the expansion 

Therefore,

4 ^th term from the end = (10-4+1)th, i.e. 7^th term from the starting.

We have a formula,

= 21000 (x)^-2

Therefore, a 4^th term from the end = 21000 (x)^-2

Conclusion : 4^th term from the end = 21000 (x)^-2