1. A: -1x²-5 car -5x+5x =0
B: 5x-2 car -x²+x² =0
2. C: 6²-15a-12a²+8a+12
C: 36-7a-12a²+12
C: 48-7a-12a²
D: -4a²+12a+7a-21
D: -4a²+19a-21
3. E: (3×3×3)+(-5×3)+3
E: 27-15+3
E: 12+3
E: 15
F: (3×3-2)(2×3+3)
F: (9-2)(6+3)
F: 7×9
F: 63
4. 36×99 = 36×100-1 =36×100-36×1=3600-36=3564
113×52 =113×50+2=113×50+113×2=5650+226= 5876
5. 16×9 =144 c'est l'aire du rectangle entier
(9-a)×(16-2a) = 9×16=144
9×(-2a)=-18a
-a×16=-16a
-a×(-2a)= 2a²
144-34a+2a²
