Question

Даю 90 балов за правильный ответ.

Answer 1

Объяснение:

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