Réponses

2013-09-29T18:51:05+02:00
Bonsoir
A = 12/25 x 15/-8
= 6/5 x -3/8 = -18/20 = - 9/10

B = -18/27 x -11/8
= -9/27 x -11/4 = 99/108 = 11/12

C = 11/5 -9/5 x 7/18
= 11/5 - 1/5x 7/2
= 11/5 - 7/10
= 22/10 - 7/10 = 15/10

D = (8/15-1/5) : 2/21
= (8/15 - 3/15) : 2/21
= 5/15 x 21/2
= 1/3 x 21/2
= 21/6 = 7/2

E = (2/3 +1/6) : (1 -1/3)
=( 4/6 +1/6 ) : (3/3 -1/3)
= 5/6 : 2/3
= 5/6 x 3/2 = 15/12 = 5/4

Exercice 2
diviseurs de 36 : 2, 3, 4, 6, 9, 12 ;
diviseurs de 42 : 2, 3, 6, 7, 21
communs = 2, 3,6
PGCD = 6
Exercice 3
2983 = 2 x 1099 + 785
1099 = 1 x 785 + 314
785 = 2 x 314 + 157
314 = 2 x 157 + 0
pgcd = 157
A = 19/7 -3/14 = 38/14 -3/14 = 35/14

Exercice 4
RL² = 2.8² + 3.2² = 7.84 + 10.24 = 18.08
RL = racine de 18.08 = 4.25 cm
RE = 4.25 - 4.1 = 0.15