Answer:
Coefficient of in is 15120
Step-by-step explanation:
We know that ) can be expanded in (n+1) terms by using binomial theorem and each term is given as
Here value of r is taken from n to 0
we have to determine the coefficient of in
in this problem we have given n=7
We have to determine the coefficient of
it means in the expansion we have to find the the 3rd power of x and therefore
r=n-3
here n=7
therefore, r=7-3=4
Hence the coefficient of can be determine by using formula
here n=7, r=4
=
=
Therefore the coefficient of in is 15120