Calculs en détaillant les étapes

B= (1 - 5/2) : (3 - 3/5)
B= (2/2 - 5/2) : (15/5 - 3/5)
B= - 3/2 : 12/5
B= - 3/2 x 5/12
B= - 3/2 x 5/(3 x 4)
B= - 5/(2 x 4)
B= - 5/8

[tex]B = (1- \frac{5}{2}):(3- \frac{3}{5})\\\\ B = (\frac{2}{2}- \frac{5}{2}):( \frac{15}{5}- \frac{3}{5})\\\\ B= \frac{-3}{2}: \frac{12}{5}\\\\ B = \frac{-3}{2}\times \frac{5}{12}\\\\ B = \frac{-15}{24} \\\\ B = \frac{-15:3}{24:3}\\\\ B = \frac{-5}{8} [/tex]