Question

Using the expansion for the binomial: ( x^3 − y^4 )^9 :The coefficient for the 6th term is

Answer 1

-126

Explanation:

For the binomial expression
`(a-b)^(n)` the coefficient of
`(r+1)^(th)` term is given by
`{n \choose r} * -1^((r))`.

We have to find the coefficient of 6th term in the binomial expansion of

`(x^(3)-y^(4))^(9)`.

Hence n=9 and r=5

The coefficient of 6th term =
`{9 \choose 5} * (-1)^(5)`

=
`-{9 \choose 5}`

= -126