Bonjour,
Exo 5
A(x)= 21x-35-9x²+15x
A(x)= -9x²+36x-35
B(x)= 2x²-12-6x²-15x
B(x)= -4x²-15x-12
C(x)= 36x²-60x+25
D(x)= 4x²-1-2(x²+2x-4x-8)
D(x)= 4x²-1-2x²+4x+16
D(x)= 2x²+4x+15
Exo 6
A(x)= (3x-2)(x+5-2x-3)
A(x)= (3x-2)(-x+2)
B(x)= [(-2x+1)-(5x+4)][(-2x+1+5x+4)]
B(x)= (-7x-3)(3x+5)
C(x)= (3x+2)(3x+2)+2(3x+2)(-2x+5)
C(x)= (3x+2)[3x+2+2(-2x+5)]
C(x)= (3x+2)(3x+2-4x+10)
C(x)= (3x+2)(-x+12)