Question

Rút gọn biểu thức:

\(x^{n-1}\left(x+y\right)-y\left(x^{n-1}+y^{n-1}\right)\)

Answer 1

\(x^{n-1}\left(x+y\right)-y\left(x^{n-1}+y^{n-1}\right)=x^n+y.x^{n-1}-y.x^{n-1}-y^n=x^n-y^n\)

Answer 2

\(x^{n-1}\left(x+y\right)-y\left(x^{n-1}+y^{n-1}\right)\)

\(=x^{n-1}x+x^{n-1}y-yx^{n-1}-y^{n-1}y\)

\(=x^n-y^n\)