Answer
$x^4+4x^3y+6x^2y^2+4xy^3+y^4$
Work Step by Step
The coefficients in the the $n=
4
$ row of Pascal's Triangle are $\{
1,4,6,4,1
\}$. Using these as the coefficients of the terms that follow the pattern in expanding binomials, the expression $
(x+y)^4
$ expands to
\begin{array}{l}
x^4+4x^3y+6x^2y^2+4xy^3+y^4
.\end{array}
