The expression is .

Compare the binomial expression with

Then .

First term  power is 1

Second term  power is -2.

So in binomial expression powers of x are in series of

9 , 8 − 2 , 7 − 2(2) , 6 − 2(3) , 5 − 2(4) , 4 − 2(5) ......0 − 2(9).

9 , 6 , 7 − 4 , 6 − 6 , 5 − 4 , 4 − 10 ...... 0 − 18.

9 , 6 , 3 , 0 , 1 , − 6 ......  − 18.

So fourth term in binomial expansion is x^o term.

So j = 9 − 4 + 1 = 6.

The formula for coefficient of x^j in the expression of is .

The coefficient of x^o in the expression of is .

The coefficient of x^o term is − 84.