Bonjour.
E = (1/7-5)×(1/7+5)
E = -34/7×(1/7+5)
E = -34/7×36/7
E = - 1224/49
F = (3/5-5/3)×7/2-(5-2/3)
F = -16/15×7/2-(5-2/3)
F = -16/15×7/2-13/3
F = -8/15×7-13/3
F = -56/15-13/3
F = - 121/15
/ = division.
Bonne soirée.
