A) 18
B) 6
C) 12
D) 10
Correct Answer: A
Solution :
\[{{T}_{r+1}}={}^{6}{{C}_{r}}{{x}^{6-r}}{{3}^{r}}\] This contains \[{{x}^{5}}\] if 6 - r = 5 \[\Rightarrow r=1\] Coefficient of \[{{x}^{5}}{{=}^{6}}{{C}_{1}}{{3}^{1}}=18.\]You need to login to perform this action.
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