Simplificar las siguientes fracciones.

1) $\frac{7a^{2}b^{3}}{9ax^{2}y}*\frac{18x^{2}c}{15ac^{4}}$

2) $\frac{21k^{2}p^{3}}{13mn^{2}}\div\frac{28p^{2}k^{3}}{39m^{2}n^{3}}$

3) $\frac{2x^{2}y}{3yz}\times\frac{5z^{2}x}{7xy^{2}}$$\div$$\frac{21x^{2}y^{3}z^{2}}{40xy^{2}z}$

4) $\frac{m^{2}}{8n}$$\times\frac{36p^{3}q^{2}}{81mn}$$\div\frac{15mpx^{5}}{27n^{2}x^{3}y}$

5) $\frac{14x^{2}-7x}{12x^{3}+24x^{2}}+\frac{2x-1}{x^{2}+2x}$

6) $\frac{a^{2}b^{2}+3ab}{4a^{2}-1}\div\frac{ab+3}{2a+1}$

7) $\frac{x^{2}-4a^{2}}{ax+2a^{2}}\times\frac{2a}{x-2a}$

8) $\frac{a^{2}-121}{a^{2}-4}\div\frac{a+11}{a+2}$

9) $\frac{16x^{2}-9a^{2}}{x^{2}-4}\times\frac{x-2}{4x-3a}$

10) $\frac{25x^{2}-9a^{2}}{x^{2}-4}\times\frac{x-2}{4x-3a}$

11) $\frac{x^{2}+5x+6}{x^{2}-1}$$\times\frac{x^{2}-2x-3}{x^{2}-9}$

12) $\frac{x^{2}+3x+2}{x^{2}+9x+20}\times\frac{x^{2}+7x+12}{x^{2}+5x+6}$

13) $\frac{2x^{2}+5x+2}{x^{2}-4}\times\frac{x^{2}+4x}{2x^{2}+9x+4}$

14) $\frac{b^{4}-27b}{2b^{2}+5b}\times\frac{4b^{2}-25}{2b^{2}-11b+15}$

15) $\frac{2x^{2}+13x+9}{4x^{2}-9}\div\frac{2x^{2}+11x+5}{4x^{2}-1}$

16) $\frac{3ax^{2}+3ax}{(a-x)^{2}}\times\frac{2a^{2}+ax-3x^{2}}{a^{2}-x^{2}}$

17) $\frac{x^{2}-14x-15}{2-4x-45}\div\frac{x^{2}-12x-45}{x^{2}-6x-27}$

18) $\frac{2+3x+5x^{2}}{(1-x)^{3}}\div\frac{4x^{2}}{1+x^{3}}$

19) $\frac{2x^{2}-x-1}{2x^{2}+5x+2}\div\frac{4x^{2}+x-14}{16x^{2}-49}$

20) $\frac{a^{2}-2ab-3b^{2}}{(a+b)^{3}}\div\frac{a^{2}-4ab+3b^{2}}{a^{3}+b^{3}}$