Exercice 3 :
1)
B = 0
4x(x+3) = 0
ssi
4x = 0
x = 0
ou
x+3 = 0
x= -3
2)
C = x² + 6x + 9
a)
C avec x=-2 ?
C = 4 - 12 + 9
C = 1
b)
(x+3)² = x² + 2.3.x + 9 = x² + 6x + 9 = C
3)
a)
B = 4x(x+3)
B = 4x² + 12x
b)
B-C = 4x² + 12x - x² - 6x - 9
B-C = 3x² + 6x - 9
c)
B+C = 4x² + 12x + x² + 6x + 9
B+C = 5x² + 18x + 9
Exercice 2 :
1)
D = ([] + 7)² - 36
D = (([] + 7) + 6)(([] + 7) - 6)
D = ([] + 13)(([] + 1)
E = 4[]² + 8[] + 4
E = (2[] + 2)
F = ([] + 13)([] + 1) - 4([] + 1)²
F = ([] + 1)([] + 13 - 4([]+1))
F = ([] + 1)(-3[] + 9)