Hoặc
Tính:
d) x+1x.x+2−x2x2−1.
d, x+1x.x+2−x2x2−1
=x+1x.x.x2−1x2−1+2−x2x2−1
=x+1x.x3−x+2−x2x+1x−1
=x+1.x3−x2−x+2x.x+1x−1
=x3−x2−x+2xx−1