Thực hiện các phép cộng, trừ phân thức sau: b) x+1/x+1-x+1/x-1 ;
Giải thích
b, x−1x+1−x+1x−1
=x−12x+1x−1−x+12x+1x−1
=x2−2x+1−x2+2x+1x+1x−1
=x2−2x+1−x2−2x−1x+1x−1
=−4xx+1x−1
b, x−1x+1−x+1x−1
=x−12x+1x−1−x+12x+1x−1
=x2−2x+1−x2+2x+1x+1x−1
=x2−2x+1−x2−2x−1x+1x−1
=−4xx+1x−1