187. 1) (x/(x^2-1)+x/(x+1)) : (4-x^2)/(x+1);

1. \(\left(\frac{x}{x^2-1}+\frac{x}{x+1}\right):\frac{4-x^2}{x+1}\);
2. \(\frac{9-u^2}{u-2}:\left(\frac{u-2}{(u+2)^2-2u}-\frac{u-2}{u^3-8}\right)\);
3. \(\left(\frac{y^2-y-1}{y-1}-1\right)\cdot\left(\frac{1}{2+y}+2y+1\right)\);
4. \(\left(\frac{4}{-4+x}-x+1\right):\left(\frac{1}{x+2}-\frac{x+2}{x^2-2x+4}\right)\);
5. \(\left(\frac{x}{y^2}-\frac{y}{x^2}\right):\left(\frac{x}{y}+1+\frac{y}{x}\right)\);
6. \(\left(\frac{1}{b^2}-\frac{1}{ab}+\frac{1}{a^2}\right):\left(\frac{a^2}{b}+\frac{b^2}{a}\right)\);
7. \(\left(\frac{1}{u^2}-\frac{1}{u^3}\right):\left(\frac{1}{u^2}-u\right)\);
8. \(\left(x+\frac{8}{x+2}\right):\left(\frac{8+x^3}{8+x^3}-\frac{1}{4-x^2}\right)\).