Réponses

  • Utilisateur Brainly
2013-09-07T19:06:58+02:00
Calculer les expressions suivantes. a= 6/7 et b= 8/5
A = a+b =86/35
B= ab =48/35
C=1/a+1/b =43/24
D= 1/a+b =83/30
E=a/b+b/a =1009/420
F= a²+b² =4036/1225
G= (a+b)² =7396/1225
H= (b-a)²
=676/1225
Je pourrais avoir les details sans tout de suite les réponses svp? Merci beaucoup !
2013-09-07T19:28:36+02:00
a= 6/7 et b= 8/5
A = a+b
6/7 + 8/5
30/35 + 56/35 = 86/35

B= ab
6/7 X 8/5 = 48/35 

C=1/a+1/b
1 + 1  = 43/24
6/7 8/5 
 D= 1/a+b
1/6/7 + 8/5 = 1 X 7/6 +8/5
                    7/6 +8/5= 35/30 + 48/30 = 83/30

E=a/b+b/a
6/7 + 8/5  = 6/7 X 5/8 + 8/5 X 7/6
8/5    6/7     30/56 + 56/30 = 900/1680 + 3136/1680 = 4036/1680 = 2018/840= 1009/420

F= a²+b²
6/7² + 8/5² = 36/49 + 64/25 =  900 /1225+ 3136/1225 = 4036/1225  
                     
G= (a+b)²
(6/7 + 8/5)² 
(30/35 + 56/35)²
(86/35)² = 7396/1225
H= (b-a)²
(8/5 -6/7)²
(56/35 - 30/35)²
(26/35)²
676/1225