Question: The coefficient of $x$ in the expansion of $(x+3)^{3}$ is
(a) 1
(b) 9
(c) 18
(d) 27
Solution:
$(x+3)^{3}$
$=x^{3}+3^{3}+9 x(x+3)$
$=x^{3}+27+9 x^{2}+27 x$
So, the coefficient of $x$ in $(x+3)^{3}$ is 27 .
Hence, the correct answer is option (d).
