Bonjour
1)
a = 2 ; b = 18 ; c = 12
A = a/b + c
A = 2/18 + 12
A = 1/9 + 12
A = 1/9 + (12 x 9) / (1 x 9)
A = 1/9 + 108/9
A = 109/9
B = (a + b) / c
B = (2 + 18) / 12
B = 20/12
B = (4 x 5) / (4 x 3)
B = 5/3.
C = a / (b + c)
C = 2 / (18 + 12)
C = 2 / 30
C = (2 x 1) / (2 x 15)
C = 1/15.
12)
a = 5 ; b = 10 ; c = 12
A = a/b + c
A = 5/10 + 12
A = (5 x 1) / (5 x 2) + 12
A = 1/2 + 12
A = 1/2 + (12 x 2) / (1 x 2)
A = 1/2 + 24/2
A = 25/2
B = (a + b) / c
B = (5 + 10) / 12
B = 15/12
B = (3 x 5) / (3 x 4)
B = 5/4.
25/2 ≠ 5/4.
Cet élève a tort.
