JEE Main202313 Apr 2023Evening ShiftMathematicsBinomial TheoremActual
The coefficient of x 5 in the expansion of 2 x 3 - 1 3 x 2 5 is
Options
- A80 9
- B9
- C8
- D26 3
Correct answer
A. 80 9
Step-by-step solution
General term of the binomial expansion of 2 x 3 - 1 3 x 2 5 is T r + 1 = 5 C r ( 2 x 3 ) 5 - r   - 1 3 x 2 r ⇒ T r + 1 = C r 5 2 5 - r - 1 3 r x 15 - 5 r For coefficient of x 5 , we must have 15 - 5 r = 5 ⇒ r = 2 So, required coefficient is = C 2 5 ( 2 ) 3 1 9 = 10 × 8 × 1 9 = 80 9