Question

Срочно помогите!!! Алгебра 10 класс!!!

Answer 1

вроде так...................................

Answer 2

$frac{1}{a(a-b)(a-c)}+frac{1}{b(b-a)(b-c)}+frac{1}{c(c-a)(c-b)}= \ \ =frac{1}{a(a-b)(a-c)}-frac{1}{b(a-b)(b-c)}+frac{1}{c(a-c)(b-c)}= \ \ frac{bc(b-c)-ac(a-c)+ab(a-b)}{abc(a-b)(b-c)(a-c)}= frac{b^2c-bc^2-a^2c+ac^2+a^2b-ab^2}{abc(a-b)(b-c)(a-c)}= \ \ frac{(b^2c-ab^2)+(a^2b-bc^2)+(ac^2-a^2c)}{abc(a-b)(b-c)(a-c)}=frac{-b^2(a-c))+b(a^2-c^2)-ac(a-c)}{abc(a-b)(b-c)(a-c)}= \ \ =frac{-b^2(a-c))+b(a-c)(a+c)-ac(a-c)}{abc(a-b)(b-c)(a-c)}= \ \ =$
$frac{(a-c)(-b^2+b(a+c)-ac)}{abc(a-b)(b-c)(a-c)}=frac{-b^2+ab+bc-ac}{abc(a-b)(b-c)}= \ \ frac{(-b^2+bc)+(ab-ac)}{abc(a-b)(b-c)}=frac{-b(b-c)+a(b-c)}{abc(a-b)(b-c)}= \ \ frac{(b-c)(a-b)}{abc(a-b)(b-c)}=frac{1}{abc}$