Ответ:

a)   [tex]\displaystyle \boldsymbol { \frac{2}{a+2 }}[/tex]

б)  [tex]\displaystyle \boldsymbol { \frac{3x^2+2}{2x^3} }[/tex]

в)   [tex]\displaystyle \boldsymbol { \frac{7+13x}{x(x+1)} }[/tex]

Объяснение:

а)

[tex]\displaystyle \frac{a-2}{a^2-4} -\frac{a-2}{4-a^2} ^{\setminus (-1)}=\frac{a-2}{a^2-4} -\bigg(-\frac{a-2}{a^2-4} \bigg)=\frac{a-2}{a^2-4} +\frac{a-2}{a^2-4} =\\\\\\=\frac{a-2}{(a-2)(a+2)} +\frac{a-2}{(a-2)(a+2)} =\frac{1}{a+2} +\frac{1}{a+2} =\frac{2}{a+2}[/tex]

б)

[tex]\displaystyle \frac{15x-2}{10x^2}^{\setminus x} +\frac{5+x}{5x^3} ^{\setminus 2} =\frac{15x^2-2x+10+2x}{10x^3} =\frac{15x^2+10}{10x^3} =\frac{5(3x^2+2)}{5*2x^3} =\\\\\\=\frac{3x^2+2}{2x^3}[/tex]

в)

[tex]\displaystyle \frac{7}{x^2+x} +\frac{13}{x+1} =\frac{7}{x(x+1)} +\frac{13}{x+1} ^{\setminus x}=\frac{7+13x}{x(x+1)}[/tex]