[tex]\frac{5}{21}-\frac{3}{14}+\frac{2}{7} =\frac{10}{42}-\frac{9}{42}+\frac{12}{42} =\frac{10-9+12}{42} =\frac{13}{42}[/tex]
[tex]\frac{9}{20}-\frac{7}{10}+\frac{2}{15} =\frac{27}{60}-\frac{42}{60}+\frac{8}{60} =\frac{27-42+8}{60} =\frac{-7}{60} =-\frac{7}{60}[/tex]
[tex]\frac{11}{20}-\left(\frac{1}{4}+\frac{1}{5}\right) =\frac{11}{20}-\frac{9}{20} =\frac{1}{10}[/tex]
Sper că te-am ajutat!
Succes!
