Question

Find the fourth term in the expansion of the binomial

(4x + y)^4
a) 16xy^3
b) 256x^4
c) 64y^4
d) 4xy^3

Answer 1

a) 16xy³

Explanation:

For a binomial expansion (a + b)ⁿ, the r+1 term is:

nCr aⁿ⁻ʳ bʳ

Here, a = 4x, b = y, and n = 4.

For the fourth term, r = 3.

₄C₃ (4x)⁴⁻³ (y)³

4 (4x) (y)³

16xy³