Answer:
If x9 is at the (r + 1)th term in the expression.
Tr+1 = nCr xn-r ar
For this term to contain x9,
40 – 3r = 9
3r = 40 – 9
3r = 31
r = 31/3
It is not possible. [r is not an integer]
Thus, there is no term with x9 in the expansion.
Does the expansion of (2×2 – 1/x) contain any term involving x9?
Does the expansion of (2×2 – 1/x) contain any term involving x9?