`#Sad`
`B= ((x^3-1)/(x^2-x)+(x^3+1)/(x^2+x)) : (2(x^2-2x+1))/(x^2-x)` `\text{(Đk:}` `x \ne 0;` `x \ne +-1)`
`B= [((x-1)(x^2+x+1))/(x(x-1))+((x+1)(x^2-x+1))/(x(x+1))] : (2(x-1)^2)/(x(x-1))`
`B= ((x^2+x+1)/(x)+(x^2-x+1)/(x)) : (2(x-1))/(x)`
`B= ((x^2+x+1+x^2-x+1)/(x)) : (2x-2)/(x)`
`B= (2x^2+2)/(x). (x)/(2x-2)`
`B= (2(x^2+1))/(x). (x)/(2(x-1))`
`B= (x^2+1)/(x-1)`