Exercice 1 :
1. A = (3/5)-(1/2)*(5/2)
A = = (3/5)-(5/4)
A = = (12/20)-(25/20)
A = -13/20
B = (3-(2/3))/((4/3)*7)
B = ((9/3)-(2/3))/(28/3)
B = (7/3)/(28/3)
B = (7/3)*(3/28)
B = 21/84
B = 1/4
Donc (d'après mes calculs) A ≠ B
2. C = (8/3)-(2/3)+(8/7)
C = (6/3)+(8/7)
C = 2+(8/7)
C = (14/7)+(8/7)
C = 22/7
D = ((-2/5)+(5/2))/((-3/4)+(1/2))
D = ((-4/10)+(25/10))/((-3/4)+(2/4))
D = (21/10)/(-1/4)
D = (21/10)*(-4)
D = -84/10
D = -42/5 (simplification par 2)
3. B = 1/4
L'inverse de B est donc 4 (4/1)
D = -42/5
L'opposé de D est donc 42/5
4. B+D
= (1/4)+(-42/5)
= (5/20)-(168/20)
= -163/20
C*D
= (22/7)*(-42/5)
= -924/35
= -132/5 (simplification par 7)
C/B
= (22/7)/(1/4)
= (22/7)*4
= 88/7
