Réponse :
Exercice 2B.3
[tex]A=\frac{3*3}{7*3} + \frac{4}{21} - \frac{10,5*5}{2*10,5} \\A= \frac{9}{21} + \frac{4}{21} - \frac{52,5}{21} \\A= \frac{9+4-52,5}{21}\\A= -\frac{39,5}{21}[/tex]
Exercice 2B.4
[tex]B=\frac{3}{5} - \frac{1}{5} * (\frac{5}{2} +\frac{2*2}{1*2} )\\B=\frac{3}{5} - \frac{1}{5} * \frac{9}{2} \\B= \frac{3}{5} - \frac{9}{10} \\B= \frac{3*3}{5*2} - \frac{9}{10} \\\\B= 0[/tex]
Exercice 2B.5
[tex]B= \frac{2}{3} - \frac{20}{6} \\B= \frac{2*2}{3*2} - \frac{20}{6} \\\\B= -\frac{16}{6}[/tex]
[tex]C= 5 + (\frac{1*8}{1*8} + \frac{1}{8} ) : \frac{3}{4} \\C= 5 + \frac{9}{8} * \frac{4}{3} \\C= 5 + \frac{36}{24} \\C= \frac{5*24}{24} + \frac{36}{24} \\\\C= \frac{120 + 36}{24} \\C= \frac{156}{24}[/tex]
