Question

Найдите значение выражения помогите пожалуйста

Answer 1

$\frac{y+7}{y^2-25}-\frac{2y+2}{y^2-25}=\frac{y+7-(2y+2)}{y^2-5^2}= \frac{y+7-2y-2}{(y-5)(y+5)}=\frac{-y+5}{(y-5)(y+5)}=\\\\ =\frac{-(y-5)}{(y-5)(y+5)}=-\frac{1}{y+5}=-\frac{1}{5.7+5}=-\frac{1}{10.7}=-\frac{10}{107}$

$\frac{9b-1}{b^2-9}-\frac{6b-10}{b^2-9}=\frac{9b-1-(6b-10)}{b^2-3^2}=\frac{9b-1-6b+10}{(b-3)(b+3)}=\frac{3b+9}{(b-3)(b+3)}=\\\\ =\frac{3(b+3)}{(b-3)(b+3)}=\frac{3}{b-3}=\frac{3}{4.5-3}=\frac{3}{1.5}=2$