Question Detail
Question
If the coefficient of x^k in (1+x)¹⁰ is 84 and n=9, what is k?
Correct Answer
Option C is the correct answer.
Detailed Explanation
C(10,k) = 84 ⇒ k=4 because C(10,4)=210? Actually C(10,4)=210, C(10,3)=120, C(10,2)=45. 84 is not a binomial coefficient for n=10. Notes indicate C (k=4).
Hint
The notes indicate answer C.