[tex]A = \frac{7}{5} - \frac{3}{5} * \frac{4}{21} = \frac{4}{5} * \frac{4}{21} = \frac{16}{105} [/tex]
[tex]B = 4 - 4 : \frac{16}{3} = 4 - \frac{4}{3} = \frac{8}{3} [/tex]
[tex]C = (1 - \frac{1}{7}) : \frac{12}{5} = \frac{6}{7} : \frac{12}{5} = \frac{6}{7} * \frac{5}{12} = \frac{5}{14} <== SIMPLIFIER[/tex]
[tex]D = ( \frac{1}{4} - \frac{1}{5}) * (7 + \frac{37}{9}) = \frac{1}{20} * \frac{100}{9} = \frac{5}{9} <== SIMPLIFIER[/tex]
