Question

cho A =\(\left(\dfrac{2+x}{2-x}-\dfrac{2-x}{2+x}-\dfrac{4x^2}{x^2-4}\right):\dfrac{x^2-6x+9}{\left(2-x\right)\left(x-3\right)}\)

Rút gọn A

cần gấp ạ, Cảm ơn!

Answer 1

Với `x \ne +-2 , x \ne 3`. Ta có:

`A = ( [ 2 + x ] / [ 2 - x ] - [ 2 - x ] / [ 2 + x ] - [ 4x^2 ] / [ x^2 - 4 ] ) : [ x^2 - 6x + 9 ] / [ ( 2 - x ) ( x - 3 ) ]`

`A = [ ( 2 + x )^2 - ( 2 - x )^2 + 4x^2 ] / [ ( 2 - x ) ( 2 +  x ) ] . [ ( 2 - x ) ( x - 3 ) ] / [ ( x - 3 )^2 ]`

`A = [ 4 + 4x + x^2 - 4 + 4x - x^2 + 4x^2 ] / [ ( 2 - x ) ( 2 + x ) ] . [ 2 - x ] / [ x - 3 ]`

`A = [ 4x^2 + 8x ] / [ ( 2 - x ) ( 2 + x ) ] . [ 2 - x ] / [ x - 3 ]`

`A = [ 4x ( x + 2 ) ] / [ 2 + x ] . 1 / [ x - 3 ]`

`A = [ 4x ] / [ x - 3 ]`

Answer 2

Mình làm nhưng ko bt có đúng không