KCET2007MathematicsBinomial Theorem
The ninth term of the expansion (3 x- 1 2 x )⁸ is
Options
- A1 512 x⁹
- B-1 512 x⁹
- C-1 256 x⁸
- D1 256 x⁸
Correct answer
D. 1 256 x⁸
Step-by-step solution
The general term of the expansion (x+a)^ n is T_ r+1 = n r x^ n-r a^ r . We have, (3 x- 1 2 x )⁸ . Here, r=8, x=3 x, a= (- 1 2 x ), n=8 Nineth term, T₉= 8 8 (3 x)⁸⁻⁸ ( -1 2 x )⁸ = 1 256 x⁸