Bonjour
Réduire au même dénominateur :
a) 5/12 et 7/18
5/12 = 5/(6 x 2)
7/18 = 7/(6 x 3)
5/12 = (5 x 3)/(12 x 3) = 15/36
7/18 = (7 x 2)/(18 x 2) = 14/36
b) (-1)/30 et (-3)/100
-1/30 = -1/(10 x 3)
-3/100 = -1/(10 x 10)
-1/30 = (-1 x 10)/(30 x 10) = -10/300
-3/100 = (-1 x 3)/(100 x 3) = -3/300
c) 2/15 et (-5)/18
2/15 = 2/(3 x 5)
-5/18 = -5/(3 x 6)
2/15 = (2 x 6)/(15 x 6) = 12/90
-5/18 = (-5 x 5)/(18 x 5) = -25/90
d) 11/60 et (-3)/35
11/60 = 11/(5 x 12)
-3/35 = -3/(5 x 7)
11/60 = (11 x 7)/(60 x 7) = 77/420
-3/35 = (-3 x 12)/(35 x 12) = -36/420
