Question

СРОЧНО. Даю 53 балла.

Answer 1

$\frac{1}{(a-b)(a-c)} -\frac{1}{(a-b)(b-c)} +\frac{1}{(c-a)(c-b)}=\frac{1}{(a-b)(a-c)} -\frac{1}{(a-b)(b-c)} +\frac{1}{(a-c)(b-c)}=\\\\=\frac{b-c-a+c+a-b}{(a-b)(a-c)(b-c)}=\frac{0}{(a-b)(a-c)(b-c)}=0$