Réponse:
4(3x-2)-4
= 4(3×2-2)-4
=4(6-2)-4
= 4×6 -2×4 -4 (c la propriété de double distributivité)
= 24 -8 -4
=16 -4
=12
(2x+6)(5-2x)
= (2×4+6)(5-2×4)
= (8+6)(5-8)
soit = 14×(-3) = -42
soit = 8×5 + 8×(-8) + 6×5 + 6×(-8)
= 40 + (-64) +30 + (-48)
= -24 +30 -48
= 6 -48
= -42
