2/
$\frac{8}{17} x = \frac{16}{15}$
$x = \frac{16}{15} : \frac{8}{17} $
$x = \frac{16}{15} . \frac{18}{8} $
$x = \frac{8.2.6.3}{5.3.8}$
$x = \frac{12}{5}$
3/
$\frac{595959}{636363}$
$=\frac{59.10000+59.100+59.1}{63.10000+63.100+63.1}$
$=\frac{59.(10000+100+1)}{63.(10000+100+1)}$
$=\frac{59}{63}$
4/