a) \(\frac{12}{17}\) : 6 = \(\frac{12}{17}\)  x \(\frac{1}{6}\) = \(\frac{12 \times 1}{17 \times 6}\) = \(\frac{12}{102}\) = \(\frac{6}{51}\)

16 : \(\frac{8}{11}\)  = 16 x \(\frac{11}{8}\) = \(\frac{16 \times 11}{8}\) = \(\frac{176}{8}\) = 22

9 : \(\frac{3}{5}\) x \(\frac{4}{15}\) = 9 x \(\frac{5}{3}\) x \(\frac{4}{5}\) = \(\frac{9 \times 5}{3}\) x \(\frac{4}{5}\) = \(\frac{45}{3}\) x \(\frac{4}{5}\) = \(\frac{45 \times 4}{3 \times 5}\) = \(\frac{180}{15}\) = 12

b)