Binomial Theorem And Its Simple Applications Question 200

Question: The coefficient of $ x^{53} $ in the expansion $ \sum\limits_{m=0}^{100}{^{100}C_{m}{{(x-3)}^{100-m}}2^{m}} $ is

Options:

A) $ ^{100}C_{47} $

B) $ ^{100}C_{53} $

C) $ {{-}^{100}}C_{53} $

D) $ {{-}^{100}}C_{100} $

Show Answer

Answer:

Correct Answer: C

Solution:

  • [c] The given sigma is the expansion of $ [(x-3)+2]100=(x-1)100=(1-x)100 $

Therefore, $ x^{53} $ will occur in $ T_{54} $ . $ T_{54}={{,}^{100}}C_{53}{{(-x)}^{53}} $

Therefore, the coefficient is $ {{-}^{100}}C_{53} $