Question

rút gọn biểu thức  -(x+1)^2-(x-1)^2

 

Answer 1

`-(x+1)^2 -(x-1)^2`

`=-(x^2+2x+1)-(x^2-2x+1)`

`=-x^2-2x-1-x^2+2x-1`

`= (-x^2-x^2)-(-2x+2x)+(-1-1)`

`=-2x^2-2`

Answer 2

\(-\left(x+1\right)^2-\left(x-1\right)^2\)

\(=-\left[\left(x^2+2x+1\right)-\left(x^2-2x+1\right)\right]\)

\(=-\left(x^2+2x+1-x^2+2x-1\right)\)

\(=-4x\)