Question

Bài 7:Rút gọn biểu thức

a.x(x-y)+y(x-y)

b.x^n-1(x+y)-y(x^n-1+y^n-1)

giúp ;-;;

Answer 1

`a, x^2 - xy + yx - y^2`

`= x^2 - y^2`

`= (x-y)(x+y)`

`b, x^n + x^(n-1)y - yx^(n-1) - y^n`

`= x^n - y^n`

 

Answer 2

`a)x(x-y)+y(x-y)`

`=(x-y)(x+y)=x^2-y^2`

`b)x^[n-1](x+y)-y(x^[n-1]+y^[n-1])`

`=x^[n-1+1]+x^[n-1]y-x^[n-1]y-y^[1+n-1]`

`=x^n-y^n`

Answer 3

`a)`\(x\left(x-y\right)+y\left(x-y\right)=\left(x-y\right)\left(x+y\right)=x^2-y^2\)

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

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

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

 

Answer 4

`a.x(x-y)+y(x-y)`

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

`=x^2-y^2`

`b.x^(n-1) (x+y)-y(x^(n-1) +y^(n-1) )`

`=x^n+x^(n-1) y-x^(n-1) y-y^n`

`=x^n -y^n`