Question

rút gọn biểu thức

x(x-y)+y(x-y)

xn-1 (x+y)-y(xn-1+yn-1)

Answer 1

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

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

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

Answer 2

\(x\left(x-y\right)+y\left(x-y\right)\)

\(=x.x-x.y+y.x-y.y\)

\(=x^2-xy+yx-y^2\)

=\(x^2-y^2\)

Answer 3

x(x-y)+y(x-y)

= x.x+x.(-y)+y.x+y.(-y)

=x^2-xy+yx-y^2

=x^2-y^2