Помогите пж),20 баллов отдам

Решите задачу:

$\frac{2a}{51 {x}^{6} y} 17 {x}^{7} y = \frac{2ax}{3} \\ \frac{24 {b}^{2}c }{3 {a}^{6} } \div \frac{16bc}{ {a}^{5} } = \\ = \frac{24 {a}^{5}{b}^{2}c }{48 {a}^{6} bc} = \frac{b}{2a} \\ \frac{5x + 10}{x - 1} \times \frac{ {x}^{2} - 1}{ {x}^{2} - 4 } = \\ = \frac{5(x + 2)}{(x - 1)} \times \frac{(x - 1)(x + 1)}{(x - 2)(x + 2)} = \\ = \frac{5(x + 1)}{x - 2}$
$\frac{y + c}{c} ( \frac{c}{y} - \frac{c}{y + c} ) = \\ = \frac{(y + c)}{c}\frac{(cy + {c}^{2} - cy)}{y(y + c)} = \\ = \frac{c}{y}$