Réponse:
exercice 24
A= 3×5+3×(-4x)= 15-12x
B= -2×3y-2×(-8)= -6y+16
C= -4×a-4×4= -4a-16
D= x×2+x×(-x)= 2x-x²
E= t×2t+t×5= 2t+5t
F= 3y×y+3y×(-2)= 3y²-6y