Yineline62

Explications étape par étape:

ex79

a = 78/36 × 72/13

a = (6×13×36×2) / (36 × 13 )

a = 6 ×2 = 12

b = 54/74 × 37/36

b = (6×9×2×37) / (37×4×9)

b = (6×2) / 4

b = 12/4 = 3

c: la photo est coupée.