Réponses

2014-01-05T15:32:13+01:00
A = 3/7 - 2/7 / 8/21

A = 3/7 - 2/7 * 21/8

A = 3/7 - 42/56 = 3/7 - 21/28 = 12/28 - 21/28

A = - 9/28

B = 5² - 2² * 9

B = 25 - 4*9 = 25-36 = -11