Solution:
the term in the expansion is
For the coefficient of set
Coefficient of x7 in is
Next, , the term in the expansion of is
For the coefficient of set
Coefficient of in the expansion of
We are given
If the coefficient of x7 in the expansion of and the coefficient of x– 7 is the expansion of are equal, then
the term in the expansion is
For the coefficient of set
Coefficient of x7 in is
Next, , the term in the expansion of is
For the coefficient of set
Coefficient of in the expansion of
We are given