Question

help me plsssssssssssssssssssssssssss

Answer 1

`(x+1)/(x-1) - (x-1)/(x+1) = 16/(x^2-1)(ĐKXĐ: x≠1 , -1)`

\(\dfrac{\left(x+1\right)\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}-\dfrac{\left(x-1\right)\left(x-1\right)}{\left(x+1\right)\left(x-1\right)}=\dfrac{16}{\left(x-1\right)\left(x+1\right)}\)

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

`=> x^2 + 2x + 1 - (x^2 - 2x + 1) = 16`

`=>x^2 + 2x + 1 - x^2 + 2x - 1  =16`

`=> 4x  = 16`

`=>x =4`

 

 

Answer 2

giúp câu c,d với help me

Answer 3

`b) (1- {x-1}/{x+1})(x+2)={x+1}/{x-1}+{x-1}/{x+1}` (ĐKXĐ:`x ne 1;-1`)

`<=> {x+1-x+1}/{x+1}(x+2)={(x+1)^{2}+(x-1)^2}/{(x-1)(x+1)}`

`<=> {2}/{x+1}(x+2)={x^{2}+2x+1+x^{2}-2x+1}/{(x-1)(x+1)}`

`<=> {2}/{x+1}(x+2)={2x^{2}+2}/{(x-1)(x+1)}`

`<=> {1}/{x+1}(x+2)={x^{2}+1}/{(x-1)(x+1)}`

`<=> (x-1)(x+2)=x^{2}+1`

`<=> x^{2}+x-2=x^{2}+1`

`<=> x=3` (thỏa mãn)