# Binomial Problems (1 Viewer)

#### Sarah182

##### Herpes Member
I can't do this topic :S

I havent had a chance to ask my teacher and my textbook doesnt have examples for these questions:

1. Find the constant term of:
(x-y)^6

2. Find the constant term of:
(3x+ (2/x^2)^9

could someone explain to me how to do this?

#### Zeber

##### Member
1. Find the constant term of:
(x-y)^6
There is no constant term here. So 0 ?
2. Find the constant term of:
(3x+ (2/x^2)^9
(3x+ (2/x^2)^9
k = 12->0 ∑ 12Ck (3x)^k*(2x)^-2(12-k)

x^0 for a constant term.

x^k.x^(-2(12-k) = x^0, equating powers.
k-24+2k = 0
3k = 24
k = 8

Plugging k = 8 into
12Ck (3x)^k*(2x)^-2(12-k)

we get the constant to be 12C8.(3^8).(2^4)

#### tacogym27101990

##### Member
Sarah182 said:
I can't do this topic :S

I havent had a chance to ask my teacher and my textbook doesnt have examples for these questions:

1. Find the constant term of:
(x-y)^6

2. Find the constant term of:
(3x+ (2/x^2)^9

could someone explain to me how to do this?