1. Представьте в виде дроби: a) $$\frac{2a}{51x^6y} \cdot 17x^7y$$; б) $$\frac{24b^2c}{3a^6} : \frac{16bc}{a^5}$$; в) $$\frac{5x + 10}{x-1} \cdot \frac{x^2-1}{x^2-4}$$; г) $$\frac{y+c}{c} : (\frac{c}{y} - \frac{c}{y+c})$$

1. a) $$\frac{2a}{51x^6y} \cdot 17x^7y = \frac{2a \cdot 17x^7y}{51x^6y} = \frac{34ax^7y}{51x^6y} = \frac{2ax}{3}$$ б) $$\frac{24b^2c}{3a^6} : \frac{16bc}{a^5} = \frac{24b^2c}{3a^6} \cdot \frac{a^5}{16bc} = \frac{24b^2ca^5}{48a^6bc} = \frac{bc}{2a}$$ в) $$\frac{5x + 10}{x-1} \cdot \frac{x^2-1}{x^2-4} = \frac{5(x+2)}{x-1} \cdot \frac{(x-1)(x+1)}{(x-2)(x+2)} = \frac{5(x+1)}{x-2}$$ г) $$\frac{y+c}{c} : (\frac{c}{y} - \frac{c}{y+c}) = \frac{y+c}{c} : (\frac{c(y+c) - cy}{y(y+c)}) = \frac{y+c}{c} : (\frac{cy + c^2 - cy}{y(y+c)}) = \frac{y+c}{c} : \frac{c^2}{y(y+c)} = \frac{y+c}{c} \cdot \frac{y(y+c)}{c^2} = \frac{y(y+c)^2}{c^3}$$