Question

Find the 4th term of the expansion of (a - sqrt(2)) ^ 8

Answer 1

Applying the binomial theorem

`{\displaystyle (x+a)^(n)=\sum _(k=0)^(n){n \choose k}x^(n-k)a^(k)}`

Here we have x = -
`√(2)`, n = 8,

=> 4th term (k = 3) would be:

`{8 \choose 3}x^(8-3)a^(3)} = {8 \choose 3}(-√(2))^(5)a^(3)} = -224a^(3)√(2)`

Hope this helps!

:)

Answer 2

A

Explanation: