NDA2023MathematicsBinomial TheoremActual
How many terms are there in the expansion of (3 x-y)^4(x+3 y)^4 ?
Options
- A9
- B12
- C15
- D17
Correct answer
C. 15
Step-by-step solution
(3 x-y)^4(x+3 y)^4=[(3 x-y)(x+3 y)]^4= (3 x^2+8 x y-3 y^2 )^4 Number of terms = 4+3-1 3-1 = ^6 C₂=15 .