Exo 1 :
A = 3✘-(7✘-5)
A = 3✘-7✘-5
A = -4✘ -5
B= -2✘+(2-5✘)
B= -2✘+2-5✘
B= -7✘ +2
2) pour x= 2 on a :
C= 3✘²-4✘+5
C= 3×2²-4×2+5
C= 9
Exo 2 :
D = 3(5✘-2)
D = 15✘ -6
E = 3✘-2(3-5✘)
E = 3✘ -6 + 10✘
E = 13✘ - 6
F= 2✘(4-3✘)-3(✘²-✘)
F= 8✘-6✘² -3✘² + 3✘
F= -9✘² + 11✘
2)
G = 21 - 28✘
G = 7×3 - 7×4✘
G = 7(3-4✘)
H = 5✘² - 2✘
H = ✘(5✘-2)
