Odpowiedź:
[tex] a)(\frac{21}{5} \times \frac{5}{4} ) \div \frac{7}{4} = \frac{7}{1} \times \frac{4}{7} = 4[/tex]
[tex]b) \frac{15}{4} \div ( \frac{23}{10} - \frac{3}{2} ) = \frac{15}{4} \div ( \frac{23}{10} - \frac{15}{10} ) = \frac{15}{4} \div \frac{8}{10} = \frac{15}{4} \div \frac{4}{5} = \frac{15}{4} \times \frac{5}{4} = \frac{75}{16} = 4 \frac{11}{16} [/tex]
