Question -
Answer -
It is known that (r +1)th term, (Tr+1), in the binomialexpansion of (a + b)n is givenby 
.
Assuming that x5 occursin the (r + 1)th term of the expansion (x +3)8, we obtain 
Comparing the indices of x in x5 andin Tr +1, we obtain
r = 3
Thus, the coefficient of x5 is 