Répondre :
a) 7+4=11
11x3=33
33-12=21
b) (5+4)x3-12 = 15
c) (X+4)x3-12
En espérant que ça t'ai aidé !
a) 7+4 = 11
11x3 = 33
33-12 = 21
b) (5+4)x3-12 = 9x3-12 = 27-12 = 15
c) x+4 = 4x
4x X3 = 12x
12x - 12 = x
11x3 = 33
33-12 = 21
b) (5+4)x3-12 = 9x3-12 = 27-12 = 15
c) x+4 = 4x
4x X3 = 12x
12x - 12 = x