Cześć!
a)
[tex]\frac{4}{5}\cdot\frac{7}{9}=\frac{4\cdot7}{5\cdot9}=\frac{28}{45}[/tex]
b)
[tex]\frac{2}{7}\cdot\frac{5}{9}=\frac{2\cdot5}{7\cdot9}=\frac{10}{63}\\\\\frac{3}{5}\cdot\frac{11}{8}=\frac{3\cdot11}{5\cdot8}=\frac{33}{40}[/tex]
c)
[tex]\frac{3}{4}\cdot\frac{13}{7}=\frac{3\cdot13}{4\cdot7}=\frac{39}{28}=\frac{28}{28}+\frac{11}{28}=1+\frac{11}{28}=1\frac{11}{28}\\\\\frac{1}{4}\cdot\frac{9}{2}=\frac{1\cdot9}{4\cdot2}=\frac{9}{8}=\frac{8}{8}+\frac{1}{8}=1+\frac{1}{8}=1\frac{1}{8}\\\\[/tex]
d)
[tex]\frac{4}{3}\cdot\frac{11}{5}=\frac{4\cdot11}{3\cdot5}=\frac{44}{15}=\frac{30}{15}+\frac{14}{15}=2+\frac{14}{15}=2\frac{14}{15}\\\\\frac{3}{7}\cdot\frac{16}{7}=\frac{3\cdot16}{7\cdot7}=\frac{48}{49}[/tex]
