Explicație pas cu pas:
[tex]a) - \frac{1}{3} - ( - 5) = - \frac{1}{3} - ( - \frac{5}{1}) = \frac{ - 1}{3} - \frac{( - 5) \times 3}{1 \times 3} = - \frac{1}{3} - ( - \frac{15}{3}) = \frac{ - 1 - ( - 15)}{3} = \frac{14}{3} = 4 \frac{2}{3} [/tex]
[tex]b) - \frac{1}{7} - ( - \frac{3}{25}) = \frac{ - 1 \times 25}{7 \times 25} - \frac{( - 3) \times 7}{25 \times 7} = - \frac{25}{175} - ( - \frac{21}{175}) = \frac{ - 25 - ( - 21)}{175} = - \frac{4}{175} [/tex]
