Question

) find the coefficient of

2

+ 7 + 5​

Answer 1

Answer:

We know that general term of expansion (a + b)"

Tr=nC (a). b

For general term of expansion (a-2b )¹2

Putting n = 12, a = a, b = -2b

.. 64%

teachoo.com

Tr.112C, (a)12-.(-2b)

=12C, (a)¹2-1. (-2)'. (b)

= 12C, (-2) (a)12-1. (b)

...(1)

We need to find coefficient of a³b7

Teachoo