Question

When using the binomial formula, which of the following is a correct step in the expansion of (x+y)^4?

Answer 1

(X+y)^2(x+y)^2
(X^2+2xy+y^2)(X^2+2xy+y^2)
X^2(x^2+2xy+y)+2xy(x^2+2xy+y)+y^2(x^2+2xy+y)

X^4+4x^3y+6x^2y^2+4xy^3+y^4 is the answer.i didn't write all the steps as I would have been too long and complicated