Tính:
Bài 8:
1, (1-x/x +x^2 - 1) : x-1/x
2, (1+1/x) . 6x/x^2-1
3, (3+1/x) . 9/9x^2-1
4, (2-3/x).x^2/4^2-9
5, (6+30/x).x/x^2 -2 5
6, (x-28/x-3)(x - 21/x+4)
1, (1-x/x +x^2 - 1) : x-1/x
2, (1+1/x) . 6x/x^2-1
3, (3+1/x) . 9/9x^2-1
4, (2-3/x).x^2/4^2-9
5, (6+30/x).x/x^2 -2 5
6, (x-28/x-3)(x - 21/x+4)