Question

Даю 70 балів!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

Ответ:

Выполнить действия .

Сложение (вычитание ) дробей с одинаковыми знаменателями .

$\bf \displaystyle \frac{3}{x}-\frac{8}{x}=\frac{3-8}{x}=-\frac{5}{x}\\\\\\\frac{12}{a}-\frac{4}{a}=\frac{12-4}{a}=\frac{4}{a}\\\\\\\frac{3x+3}{3x+15}+\frac{12}{3x+15}=\frac{3x+3+12}{3x+15}=\frac{3x+15}{3x+15}=1\\\\\\\frac{14+x}{14-5x}-\frac{6x}{14-5x}=\frac{14+x-6x}{14-5x}=\frac{14-5x}{14-5x}=1$    

$\bf \displaystyle \frac{25}{y+5}-\frac{y^{20}}{y+5}=\frac{25-y^{20}}{y+5}\\\\\\{}\ \ \ \frac{25}{y+5}-\frac{y^{2}}{y+5}=\frac{25-y^{2}}{y+5}=\frac{(5-y)(5+y)}{y+5}=5-y\\\\\\\frac{b^2}{b-7}-\frac{49}{b-7}=\frac{b^2-49}{b-7}=\frac{(b-7)(b+7)}{b-7}=b+7\\\\\\\frac{a^2+b^2}{(a-b)(a+4)}-\frac{2ab}{(a-b)(a+4)}=\frac{a^2+b^2-2ab}{(a-b)(a+4)}=\frac{(a-b)^2}{(a-b)(a+4)}=\frac{a-b}{a+4}\\\\\\\frac{x^2+y^2}{(y+16)(x+y)}+\frac{2xy}{(y+16)(x+y)}=\frac{(x+y)^2}{(y+16)(x+y)}=\frac{x+y}{y+16}$