Bonjour,
Ex. 2 :
z² = z × z
7a = 7 × a
6ab = 6 × a × b
5 - 2t = 5 - 2 × t
5a + 2b = 5 × a + 2 × b
Ex. 3 :
a) 5 + u
b) 2 × u
c) 7 × u
Ex. 4 :
5(a+4) = 5 × 4 + 5 × 4 = 5a + 20
6(4-a) = 6 × 4 - 6 × a = 24 - 6a
3(2b+5) = 3 × 2b + 3 × 5 = 6b + 15
2(7-3b) = 2 × 7 - 2 × 3b = 14 - 6b
-4(x+2) = -4 × x - 4 × 2 = -4x - 8
tu essayes de faire les deux derniers ?