Đáp án:
S={3}
Giải thích các bước giải:
f)
`(1-(x-1)/(x+1))(x+2)=(x+1)/(x-1)+(x-1)/(x+1)(ĐKXĐ: x\ne +-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))`
`<=>2/(x+1) (x+2)=(2x^2+2)/((x-1)(x+1))`
`<=>(2(x+2)(x-1))/((x-1)(x+1))=(2x^2+2)/((x-1)(x+1))`
`<=>2x^2+2x-4-2x^2-2=0`
`<=>2x-6=0`
`<=>x=3`(t/m)
Vậy` S={3}`
