Question

Determine the term containing y^5 in the expansion of (x-3y)^8

Answer 1

• -13608x³y⁵

Explanation:

Since y has degree of 5, x has degree of:

• 8 - 3 = 5

The required term of the given binomial expansion (x - 3y)⁸ is:

• 8C₅(x³)(-3y)⁵,

The value of the constant:

• 8C₅ = 8!/5!(8-5)! = 7*8 = 56 * (-3)⁵= -13608

So the full term is:

• 336x³(-3)⁵y⁵ = -13608x³y⁵