Let’s 

Let’s  try it for (x+y)^4, \(\left(x+y\right)^4\),  by looking at row 4 of Pascal’s triangle we see that we obtain x^4+4x^3y+6x^2y^2+4xy^3+y^4. \(x^4+4x^3y+6x^2y^2+4xy^3+y^4\).  We see that the coefficients match the row 4 \(4\)  of Pascal’s triangle.