Объяснение:

[tex] \frac{b + 4}{16 - b { }^{2} } - \frac{4}{4b - b {}^{2} } =\frac{b+4}{\left(b-4\right)\left(-b-4\right)}-\frac{4}{4b-b^{2}} =\frac{-\left(-b-4\right)}{\left(b-4\right)\left(-b-4\right)}-\frac{4}{4b-b^{2}} =\frac{-1}{b-4}-\frac{4}{4b-b^{2}} =\frac{-1}{b-4}-\frac{4}{b\left(-b+4\right)} = \frac{-b}{b\left(b-4\right)}-\frac{4\left(-1\right)}{b\left(b-4\right)} =\frac{-b-4\left(-1\right)}{b\left(b-4\right)} =\frac{-b+4}{b\left(b-4\right)} =\frac{-\left(b-4\right)}{b\left(b-4\right)} =\frac{-1}{b} =-\frac{1}{b}[/tex]

Ответ:

-1/b

Объяснение:

(b*(b+4)-4*(4+b))/(b*(b-4)*(b+4))=(b²+4b-16-4b)/(-b*(b²-16)=-1/b