Question 11
Binomial TheoremFind the fourth term of the binomial expansion of (x − k)5 in descending powers of x.
- A.10x2k3
- B.5x3k2
- C.−5x3k2
- D.−10x2k3
Show the answer and explanation
Answer: D (−10x2k3)
Explanation
The fourth term is ⁵C₃ x²(−k)³ = 10x²(−k³) = −10x²k³.