Réponses

2013-10-29T18:57:52+01:00
(7/4+5)au carre = 
7/4 =1.75  
1.75+5=6.75
6.75 au carre = 45.5625

(7/4-5) au carre =
7/4=1.75
1.75-5 = -3.75 
-3.75 au carre = -14.0625

45.5625-14.0625= 31.5
1.75-5 = -10.5625
euh -3.25
-3.25 au carre = 10.5625
45.5625-10.5625 = 35
2013-10-29T19:03:45+01:00
    (7/4+5)²-(7/4-5)²
=[(7/4)²+2*(7/4)*5+5²]-[(7/4)²-2*(7/4)*5+5²
=[(49/16)+(70/4)+25]-[(49/16)-(70/4)+25
=(49/16)+(70/4)+25-(49/16)+(70/4)-25
=140/4
=35