Question

thu gọn (x-2)^2-(x-2).(x+3)

b) (x+1)^2 +(x-3)^2-2.(x+1).(x-3)

 

Answer 1

Ta có : \(\left(x-2\right)^2-\left(x-2\right)\left(x+3\right)=\left(x-2\right)\left(x-2-x-3\right)\)

\(=-5\left(x-2\right)\)

Ta có : \(\left(x+1\right)^2+\left(x-3\right)^2-2\left(x+1\right)\left(x-3\right)\)

\(=\left(x+1-x+3\right)^2=4^2=16\)

Answer 2

`(x-2)^2-(x-2)(x+3)`

`=x^2-4x+4-(x^2+3x-2x-6)`

`=x^2-4x+4-x^2-x+6`

`=-5x+10`

`b)(x+1)^2+(x-3)^2-2(x+1)(x-3)`

`=(x+1)^2-2(x+1)(x-3)+(x-3)^2`

`=[(x+1)-(x-3)]^2`

`=(x+1-x+3)^2`

`=4^2=16`